Liquid Processing Nozzle

Abstract

To provide a liquid treatment nozzle that stores a cavitation core in a casing body forming a nozzle casing and prevents slip-off prevention of the cavitation core by a core presser screwed with the cavitation core which prevents defects to cause undesired separation in the casing body and the core presser when the liquid treatment nozzle is removed from a piping system of an assembly destination.SOLUTION: On a first side end of a casing body 50B and a second side end of a core presser 50A, a nozzle side screw joint part screwed with a first screw joint of a piping system is formed on one end thereof, and a cap nut 50c screwed with a male screw part forming a second screw joint of the piping system is rotatably fit into the other end thereof.SELECTED DRAWING: Figure 2

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 a venturi or orifice to create a throttle section in a water flow path, causing dissolved air to precipitate as fine bubbles due to the reduced pressure effect created when the water passes through at a high flow rate (Patent Documents 1 to 7 and Patent Document 9). In particular, the methods disclosed in Patent Documents 1 and 2 involve placing a screw member in the middle of the flow path and further increasing the speed of the water flow in the thread roots or the gap formed between opposing screw members. These methods are said to improve cavitation efficiency and generate nanobubbles at a higher density. Here, to improve cavitation efficiency, it is important to increase the arrangement density (valley point density) of the screw roots, which are cavitation points, within the cross section of the flow path.

[0003] For example, Patent Documents 1, 2, and 7 propose improving the density of valley points within a cross section by arranging multiple screw members around the center of the cross section on the same plane within the cross section of a flow channel. These documents also disclose that it is possible to arrange multiple screw members at offset positions relative to one another in the central axial direction (flow direction) of the liquid flow channel, thereby allowing the liquid flow to repeatedly come into contact with valleys that become cavitation points, which can contribute to further improving the efficiency of generating fine bubbles and the efficiency of dissolving gas.

[0004] In the configuration of the liquid treatment nozzle described above, Patent Document 9, for example, discloses a configuration in which the cavitation core, which has many threaded members and therefore requires a large number of assembly steps, is separated and separated from the nozzle casing. According to this configuration, the cavitation core is pre-assembled externally and the assembly is then attached to the nozzle casing, simplifying the assembly process of the entire nozzle. For example, in FIG. 2 of Patent Document 9, the cavitation core is housed in the casing body forming the nozzle casing, and a core retainer that screws into the cavitation core prevents the cavitation core from coming loose. The threaded joint of the core retainer is an internal thread, and a hexagonal tool engagement portion is formed on its outer periphery. The liquid treatment nozzle is incorporated into a piping system by threadedly fastening threaded joints formed on both ends of the nozzle casing to threaded joints on the piping system side. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO2016 / 178436 publication [Patent Document 2] WO2016 / 195116 publication [Patent Document 3] WO2013 / 011570 publication [Patent Document 4] WO2010 / 055702 publication [Patent Document 5] WO2013 / 012069 publication [Patent Document 6] Japanese Patent Application Laid-Open No. 2011-240206 [Patent Document 7] Patent No. 6762461 [Patent Document 8] Japanese Patent Application Laid-Open No. 2002-263678 [Patent Document 9] Patent No. 6762461 Summary of the Invention [Problem to be solved by the invention]

[0006] When removing the liquid processing nozzle disclosed in Patent Document 9 from a piping system, the following problem may occur. Specifically, in this process, a wrench is first engaged with the tool engagement portion of the core holder to prevent rotation of the core holder, while another wrench is used to rotate the piping side to unscrew the core holder from the piping. Then, the wrench engaged with the tool engagement portion of the core holder is rotated to unscrew the casing body from the piping. However, if the casing body and the piping are severely stuck together, the core holder will loosen from the casing body before the casing body and the piping are unscrewed, resulting in an unintended separation of the casing body and the core holder, which form the nozzle casing. This problem can also occur when the tool engagement portion is formed on the casing body.

[0007] The object of the present invention is to prevent the problem of unintended separation of the casing body and the core holding portion when removing a liquid treatment nozzle in which a cavitation core is housed in a casing body that forms a nozzle casing and a core holding portion that screws into the nozzle to prevent the cavitation core from coming loose. [Means for solving the problem]

[0008] The present invention relates to a liquid treatment nozzle that is incorporated into a piping system for circulating a liquid, and is provided with a nozzle casing having a housing passage section that is open at both ends, and a through-type liquid passage formed with a liquid inlet opening at one end face and a liquid outlet opening at the other end face, the nozzle casing being arranged in the housing passage section in a positional relationship such that liquid supplied toward the inlet-side opening formed in the nozzle casing can flow through the liquid passage and out of the outlet-side opening of the nozzle casing, the core body having a screw attachment hole formed therethrough from the outer peripheral surface to the inner peripheral surface of the liquid passage, and a cavitation core having a head and a screw member with the base ends of the legs held in the screw attachment hole of the core body and the tip ends of the legs protruding from the inner surface of the liquid passage, the cavitation core causing dissolved gas in the liquid to precipitate in a supersaturated state by the pressure reduction effect when the liquid that comes into contact with the cavitation treatment section increases in speed within the thread roots, and the nozzle casing is provided with a nozzle casing having a housing passage section that is open at both ends and a nozzle casing having a nozzle casing having a nozzle casing having a housing passage section that is open at both ends and a liquid outlet opening at the other end, the nozzle casing being arranged in a positional relationship such that liquid supplied toward the inlet-side opening formed in the nozzle casing can flow through the liquid passage and out of the outlet-side opening of the nozzle casing, the nozzle casing having a nozzle casing having a housing passage section that is open at both ends and a liquid outlet opening at the other end The nozzle casing consists of a casing body constituting the first side and a core holding portion constituting the second side, and the casing body has a storage passage portion formed in the form of an opening for a core insertion port on its second side end face, the second side end of the casing body extends beyond the second side end face of the cavitation core inserted in the storage passage portion, and an assembly female thread portion is formed on the inner peripheral surface of the second side end, and an assembly male thread portion is formed on the outer peripheral surface of the first side end of the core holding portion that screws into the assembly female thread portion of the casing body, and by screwing and fastening the assembly male thread portion to the assembly male thread portion, the core holding portion abuts its first side end face against the outer peripheral edge portion of the second side end face of the cavitation core to prevent it from coming out, and a nozzle side threaded joint portion that screws into a first threaded joint of the piping system is engraved on one of the first side end of the casing body and the second side end of the core holding portion, and a cap nut that screws into a male thread portion that forms a second threaded joint of the piping system is freely fitted on the other.

[0009] In the above configuration, a nozzle side screw joint portion that screws into the first screw joint of the piping system is engraved on one of the first side end of the casing body and the second side end of the core holding portion, and a cap nut that screws into the male thread portion that forms the second screw joint of the piping system is rotatably fitted on the other.Therefore, by engaging a tool with the cap nut and rotating it, the screw-fastened state between the cap nut and the piping system can be released without affecting the screw-fastened state between the casing body and the core holding portion, and thus the problem of unintended separation of the casing body that forms the nozzle casing and the core holding portion can be effectively prevented.

[0010] For example, when the cap nut is rotatably fitted to the second end of the core retainer, the outer circumferential surface of the casing body may be provided with a tool engaging portion having at least one pair of parallel surfaces for engaging a fastening tool used when assembling the liquid treatment nozzle to a piping system. After releasing the threaded fastening state between the cap nut on the core retainer side and the corresponding piping, by engaging and rotating the tool engaging portion formed on the outer circumferential surface of the casing body with a wrench or the like, the threaded fastening state between the cap nut on the core retainer side and the corresponding piping can be smoothly released without damaging the casing body.

[0011] In this case, a tool engagement hole, which forms part of the liquid flow path and is used to engage an assembly tool used to threadably fasten the male assembly thread of the core presser to the female assembly thread of the casing body, can be formed through the second end of the core presser. With this configuration, the male assembly thread of the core presser and the female assembly thread of the casing body are threaded together, and then tools are engaged with the tool engagement portion of the casing body and the tool engagement hole of the core presser, respectively, and rotated relative to each other about the axis, thereby smoothly and easily completing assembly of the nozzle casing. Furthermore, after assembly is complete, the tool engagement hole of the core presser can be reused as part of the liquid flow path, which also contributes to simplifying the structure of the liquid processing nozzle.

[0012] Furthermore, the casing main body can be provided with an additional function part that adds additional functions to the liquid treatment nozzle. By incorporating such a second main body into the casing main body, additional functions can be easily added to the liquid treatment nozzle.

[0013] The type of additional function added to the liquid processing nozzle by the additional function unit is not particularly limited. For example, the additional function unit can be provided with a flow path adjustment valve for continuously or stepwise switching the flow path cross-sectional area of ​​the liquid flow path. This makes it possible to easily adjust the flow rate of the piping system in which the liquid processing nozzle is incorporated using the flow path adjustment valve. Note that the concept of switching the flow path cross-sectional area also includes blocking the flow path. In this case, switching the flow path between two states, a fully closed state (blocked state) and a fully open state (open state), is also included in the concept of "stepwise switching the flow path cross-sectional area."

[0014] The additional function unit can also be configured to include a branch pipe for branching off and circulating the liquid from the liquid flow path. By providing such a branch pipe, the function of distributing the liquid outside the piping system in which the liquid processing nozzle is incorporated can be integrated into the casing main body, thereby simplifying the configuration of the branch piping system.

[0015] The branch pipe may be used in any manner, including, for example, a chemical solution holding section at the end of the branch pipe opposite the end connected to the second main body of the casing body, which receives the liquid from the branch pipe and dissolves the chemical solution into the received liquid, and the liquid in the branch pipe from which the chemical solution has dissolved flows back out from the end connected to the casing body of the branch pipe to the liquid flow path in a slow reverse flow manner. This configuration allows for the liquid treated by the liquid treatment nozzle to be continuously injected with an appropriate amount of chemical solution into the liquid flowing through the piping system, thereby achieving the combined effects of chemical solution and cavitation treatment with a simple configuration. For example, if the chemical solution is a cleaning chemical, the added effect of improving the permeability of the liquid due to cavitation can further improve the cleaning power of the liquid, or the amount of chemical solution injected can be reduced to maintain the same level of cleaning power.

[0016] Furthermore, the liquid processing nozzle of Patent Document 9 has the following problems. Since the straightening element is installed only downstream of the cavitation core, the effect of the straightening element is limited to suppressing the coalescence of fine bubbles that have stopped growing at the collision point of the cavitation core. Due to the relationship with the threaded joint on the piping system, the installation direction of the liquid treatment nozzle to the piping system may be reversed from the normal installation direction. In this case, the liquid flow will go from the flow straightening element to the cavitation core, and the flow straightening element will not function as intended. When assembling a liquid treatment nozzle, the flow straightening element and the cavitation core must be attached to the nozzle casing in order, which increases the number of steps.

[0017] To solve the above problems, the cavitation core can be configured as follows: That is, the liquid flow path of the core body of the cavitation core has a section including the midpoint of the central axis of the liquid flow path as a throttle section having a cylindrical surface form, and the sections before and after the throttle section of the liquid flow path have a pair of enlarged diameter sections each having a diameter larger than that of the throttle section, and a screw attachment hole is disposed in the throttle section together with a screw member, and a flow straightening member is disposed inside each of the enlarged diameter sections in a form integrated with the core body.

[0018] The airflow straightening member can be a star-shaped airflow straightening member formed by folding a metal elastic belt-like member in a zigzag shape so that peaks and valleys alternate along the folds in the direction of the short side, and then rolling the member around an axis parallel to the short side to form a star-shaped cross section. The star-shaped airflow straightening member is inserted into the expanded diameter section with the short side aligned with the axis of the expanded diameter section. When a flow is supplied to the end face of such a star-shaped airflow straightening member in the axial direction, separation flow is significantly formed at the edge of the metal elastic belt-like member. As a result, the amount of bubbles generated by the preliminary cavitation treatment upstream of the cavitation core can be increased, and the density of microbubbles generated can be further increased.

[0019] In this case, the inner circumferential surface of the expanded diameter portion can be a cylindrical surface having a larger diameter than the constricted portion and can be connected to the constricted portion via a stepped surface. The star-shaped airflow straightener, which is formed to have a larger diameter than the inner diameter of the expanded diameter portion in its free state, is press-fitted into the expanded diameter portion while elastically contracting in the radial direction relative to the axis, and can be integrated with the core body in such a way that the outer circumferential surface is gripped by the inner circumferential surface of the expanded diameter portion due to an elastic restoring force in the radial direction with its front end abutting the stepped surface. This makes it less likely that the star-shaped airflow straightener will fall off the core body, stabilizing the process of attaching the assembly of the airflow straightener and core body to the nozzle casing.

[0020] The requirements that can be added to the present invention will be explained in more detail below. Patent Documents 1 and 2 mention that, among the valleys formed within the cross section of a liquid processing nozzle, those that function most prominently as cavitation points are those located in the central region of the cross section where the liquid flow velocity is high, particularly those located within a region from the central axis to 70% of the radius of the flow path cross section (70% valleys). For example, Patent Document 2 proposes, as disclosed in FIG. 8 and elsewhere, increasing the density of valleys within the cross section by arranging multiple screw members around the central axis on the same plane within the flow path cross section. The same document also discloses that multiple screw members can be arranged at offset positions relative to one another in the axial direction (flow direction) of the liquid flow path, thereby allowing the liquid flow to repeatedly come into contact with the valleys that become cavitation points, contributing to further improvements in the efficiency of generating microbubbles and the efficiency of dissolving gas (page 5, lines 9-13).

[0021] In the configuration disclosed in Patent Document 2, the 70% valley density is calculated as the value obtained by dividing the number of 70% valleys by the cross-sectional area (70% cross-sectional area) of the flow area formed as a void in an area within 70% of the radius of the flow path cross section, and the density was 1.8 (counts / mm 2) is the maximum value. In this specification, as will be described later, the value obtained by dividing the number of 70% valleys by the total cross-sectional area of ​​the flow path, including the area occupied by the threaded portion, is adopted as the definition of the 70% valley area density. If the 70% valley area density of the nozzle test piece numbered 106 in Patent Document 2 is converted to the 70% valley area density defined above, it becomes 1.1 (number / mm 2 ) is the value.

[0022] In the screw member arrangement disclosed in Patent Document 2, the value of the 70% valley point area density is 1.1 (pieces / mm 2 ) is considered to be approximately the limit. The reason for this is that, as described in line 50 on page 4 of the document, the tip of the screw member converges toward the central axis from three or more directions, and therefore there is an area near the center of the flow path cross section where it is geometrically impossible to arrange valley points. Furthermore, the liquid flow path disclosed in Patent Document 2 has an inner diameter D of 7 mm or less, and the resulting flow rate is up to approximately 25 L / min at a liquid pressure of 0.1 MPa (see lines 58 to 64 on page 4 of the document). For specific examples of nozzles with such high flow rates, it is suggested that the leg length be increased to match the flow path inner diameter. In this case, the flow cross-sectional area of ​​the flow path increases in proportion to the square of the flow path inner diameter, while the number of valley points increases only in proportion to the leg length of the screw, and therefore the flow path inner diameter. Therefore, with this method, the density of valley points rapidly decreases as the flow path inner diameter increases, and it can be said that sufficient cavitation efficiency may not be achieved.

[0023] In this case, it is conceivable to ensure valley point density by increasing the number of threaded members arranged on the same surface, but the increased occupied area rate of the threaded members creates a dilemma in that it becomes impossible to obtain a flow rate commensurate with the inner diameter of the cross section of the flow path. Also, in the case of a nozzle with a relatively small inner diameter D, an increase in the occupied area rate of the threaded members rapidly increases pressure loss, and if liquid is to be circulated at normal tap water pressure (approximately 0.03 to 0.2 MPa), there is a concern that the reduced flow velocity will impair cavitation efficiency.

[0024] To solve the above-mentioned new problem, the following configuration is considered as a prerequisite. Specifically, the cavitation core includes a plurality of threaded members each having a thread pitch and a thread root depth of 0.10 mm to 0.40 mm and a nominal thread diameter M of 1.0 mm to 2.0 mm, forming a cavitation treatment unit. The cavitation treatment unit includes a plurality of imaginary thread arrangement surfaces perpendicular to the central axis of the liquid flow path, along the central axis. The threaded members are distributed among two or more thread arrangement surfaces, with the longitudinal direction of their legs aligned with the thread arrangement surfaces. A liquid containing dissolved gas is circulated from a liquid inlet to a liquid outlet, and the cavitation treatment unit accelerates the flow of the liquid and brings it into contact with the thread roots formed on the outer peripheral surfaces of the legs of the threaded members, thereby subjecting the liquid to cavitation treatment based on reduced pressure deposition of the dissolved gas. To solve the above-mentioned new problem, the cavitation treatment unit preferably has the following configuration.

[0025] A total of eight or more threaded members are arranged in a manner that distributes them among two or more thread arrangement surfaces (hereinafter, a group of threaded members arranged on one thread arrangement surface is also referred to as a "face thread set"). On each screw arrangement surface, the in-plane flow area ratio, defined as the ratio of the liquid flow area to the total cross-sectional area of ​​the liquid flow path, is secured to be 40% or more, and the area of ​​the liquid flow area of ​​the liquid flow path (total flow cross-sectional area) is 3.8 mm 2 More than this is ensured. The 70% valley point area density is defined as the total number of valley points located within 70% of the radius of the liquid flow path from the central axis of the liquid flow path when projected onto a plane perpendicular to the central axis, for all thread arrangement surfaces, divided by the cross-sectional area of ​​the liquid flow path. The 70% valley point area density is 2.0 points / mm 2 More than this is ensured. The distance between adjacent thread arrangement surfaces in the central axial direction is ensured to be equal to or greater than the nominal thread diameter.

[0026] By adopting the above-mentioned configuration, it is possible to dramatically improve the 70% valley point density while ensuring a sufficient liquid flow velocity even with normal tap water pressure, and in particular, even in a high-flow nozzle with a significantly enlarged flow path cross-sectional area, it is possible to ensure a sufficient 70% valley point density with a simple structure. This will be explained in detail below.

[0027] The reasons for setting the numerical ranges for the thread pitch and thread root depth of the threaded member as described above are as follows. First, if the thread root depth is less than 0.10 mm, the flow throttling effect at the thread root is insufficient. If the thread root depth is 0.40 mm or greater, the contact area between the liquid flow and the thread root becomes too large, resulting in significant flow velocity loss due to pressure loss. In either case, sufficient flow velocity cannot be ensured at the thread root, and the density of microbubble nucleation is likely to decrease. As a result, the effects unique to cavitation-treated liquids, such as improved liquid permeability, cannot be fully achieved. Furthermore, the violent bumping-like generation of microbubbles results in insufficient turbulent agitation of the liquid, which makes the precipitated bubbles more likely to grow, thereby reducing the microbubble generation efficiency.

[0028] Furthermore, if the thread pitch is increased to 0.40 mm or more, the number of thread roots per unit length of the leg decreases, making it impossible to improve the areal density of 70% root points. Therefore, the thread pitch and thread root depth should be set to 0.10 mm or more and 0.40 mm or less. Furthermore, from the perspective of ensuring the strength of the threaded member, preventing the cross section of the flow path from being excessively occupied by the threaded member, and ultimately ensuring sufficient liquid flow even with normal liquid supply pressures similar to tap water pressure, the nominal thread diameter of the threaded member should be set to 1.0 mm or more and 2.0 mm or less. This range of nominal thread diameter values ​​is approximately the same as the range of nominal thread diameters for JIS coarse pitch threads, which covers the above-mentioned thread pitch and thread root depth. The above technical premise is the same as that of Patent Document 2.

[0029] For example, Patent Document 8 discloses a device in which cylindrical bodies with multiple radially extending protrusions are stacked inside an outer cylinder, and compressed air is sprayed from the bottom of the outer cylinder into the wastewater filled inside the cylinder, causing the resulting water flow to come into contact with the protrusions of the cylinder, thereby generating cavitation (see, for example, Figure 6). However, this device does not employ the configuration of the liquid treatment nozzle of the present invention, in which wastewater flows into the outer cylinder from one end and out the other, and therefore the velocity of the water flow contacting the protrusions is extremely low. As a result, the turbulent agitation effect of the liquid due to the violent bumping of microbubbles is insufficient, and the precipitated bubbles are more likely to grow, resulting in a significant decrease in the efficiency of microbubble generation. Furthermore, the idea of ​​using a threaded member with a thread root depth, thread pitch, or nominal thread diameter, as proposed above as a preferred embodiment of the present invention, is not disclosed at all. From this perspective, it seems unlikely that any effects specific to cavitation-treated liquids, such as improved liquid permeability, can be expected.

[0030] It is desirable to arrange a total of eight or more such screw members in the liquid flow path. This corresponds to the maximum number of screw members that can be arranged in one liquid flow path in Patent Document 2 (page 4, line 56). Furthermore, rather than arranging these eight or more screw members densely in one screw arrangement surface, it is possible to more easily increase the 70% valley point density by dividing them into multiple (two or more) surface thread sets and distributing them across multiple screw arrangement surfaces.

[0031] If the in-plane flow area ratio on each thread arrangement surface becomes too small, the contact area between the water flow and the threaded parts becomes excessive, resulting in a significant decrease in flow rate due to pressure loss.As a result, the area where sufficient flow velocity can be obtained when liquid flows under normal water pressure becomes smaller than 70% of the radius from the central axis, and it becomes impossible to ensure a sufficient number of valleys that function effectively as cavitation points.Furthermore, even if the in-plane flow area ratio is relatively large, if the absolute value of the area of ​​the liquid flow region becomes too small due to a reduction in the inner diameter of the flow path cross section, the flow rate will similarly decrease significantly.

[0032] As a result of careful consideration of this situation, the inventors of the present invention have found that the in-plane flow area ratio is secured to 40% or more on each screw arrangement surface, and the area of ​​the liquid flow area is 3.8 mm 2 It was found that if the above conditions are ensured, the above problems are resolved and the pressure loss when the liquid flow passes through each thread arrangement surface is significantly reduced. Furthermore, by ensuring that the spacing between adjacent thread arrangement surfaces (surface thread assemblies) is equal to or greater than the nominal thread diameter of the threaded members used, even if multiple surface thread assemblies that satisfy the above conditions are arranged in a row along the central axis of the liquid flow path, the increase in pressure loss compared to when a single surface thread assembly is arranged can be kept extremely small, and even though more threaded members than conventionally are arranged in one liquid flow path, the required flow velocity within the cross section can be sufficiently ensured. As a result, the 70% valley point area density can be increased to 1.6 / mm, which was previously difficult to achieve. 2 When set to the above, sufficient flow velocity is ensured at the screw root, which forms the 70% valley point, resulting in a liquid treatment nozzle with extremely excellent cavitation efficiency.

[0033] If the in-plane flow area ratio is less than 40% on each screw arrangement surface, or the area of ​​the liquid flow area is 3.8 mm 2 If the distance between adjacent two thread arrangement surfaces (thread sets) is smaller than the nominal thread diameter of the threaded component used, the combined pressure loss of the two thread sets will be large, and similarly, it may be impossible to ensure a sufficient flow rate at the thread roots that form the 70% valley point.

[0034] Patent Document 2 also suggests a configuration in which multiple screw members are arranged at offset positions relative to one another along the central axis of the liquid flow path. However, the only specific example disclosed is a configuration in which a total of four screw members are divided into two pairs of two screw members, each offset along the central axis (see Patent Document 2: Figure 19), which does not contribute to a 70% increase in thread root area density. Furthermore, there is no mention of the effect on pressure loss during liquid flow if the total number of screw members is increased beyond that of the configuration described above. For example, Patent Document 2, page 5, lines 9-13, states, "Multiple collision sections can be provided in the flow direction, allowing the flow to repeatedly come into contact with the valleys that become cavitation points, thereby contributing to further improvements in the efficiency of microbubble generation and the gas dissolution efficiency described below." However, this does not provide any specific suggestions for solutions to suppress the increase in pressure loss when multiple collision sections are provided in the flow direction.

[0035] In the liquid processing nozzle having the above configuration, the area of ​​the liquid flow region of the liquid flow path is more preferably 5.0 mm 2 The inventors have created liquid treatment nozzles in which the area of ​​the liquid flow region is changed in various ways while ensuring an in-plane flow area ratio of 40% or more, and have conducted water flow tests at normal tap water pressure. As a result, it has been found that the area of ​​the liquid flow region is 5.0 mm 2 In the above cases, the flow rate tends to increase almost linearly as the area increases, whereas in the 5.0mm 2 It was found that below this value, the flow rate deviates from the linear relationship and decreases rapidly depending on the logarithm of the area of ​​the liquid flow region. This is because, under normal water pressure conditions, the area of ​​the liquid flow region is 5.0 mm 2 When the value is less than 5.0 mm, the pressure loss increases rapidly with each additional thread insertion in the nozzle, and it becomes impossible to obtain a flow rate commensurate with the cross-sectional area. Therefore, in order to increase the number of threads and further increase the 70% valley point area density, the area of ​​the liquid flow region must be increased to 5.0 mm 2 In this case, the 70% valley point area density is 2.0 pieces / mm 2(The maximum value disclosed in Patent Document 2 is 1.1 pieces / mm 2 ) or more).

[0036] The threaded members on the threaded arrangement surface are preferably positioned so that the longitudinal direction of their legs coincides with the diameter of the circular axial cross section of the liquid flow path. By aligning the longitudinal direction of their legs with the diameter of the circular axial cross section of the liquid flow path, the tips of the threaded members are closer to the central axis of the liquid flow path, where the flow velocity is highest, which is advantageous for increasing the number of 70% valley points. In this case, by providing two or more threaded arrangement surfaces containing three or more threaded members along the central axis, the 70% valley point area density of the entire nozzle can be significantly improved, significantly increasing the cavitation generation efficiency. Furthermore, by arranging the three or more threaded members on the threaded arrangement surface so that the tip faces of the legs of each thread surround the central axis to form a central gap, the flow at the center of the cross section (central flow), where the flow velocity is highest, is less likely to be obstructed by the formation of a liquid flow gap, further improving the cavitation generation efficiency.

[0037] The screw members are preferably arranged on adjacent screw arrangement surfaces in a positional relationship where their longitudinal directions coincide with each other when projected onto a plane. This configuration makes it possible to realize a liquid treatment nozzle that has particularly low pressure loss despite allowing contact with a large number of screw members, and ultimately a liquid treatment nozzle that has low pressure loss while dramatically increasing the number of 70% valley points.

[0038] In a liquid treatment nozzle of this configuration, pressure loss is unlikely to increase even when the distance between adjacent thread arrangement surfaces (flush thread assemblies) is brought close to the limit value equal to the nominal thread diameter of the threaded member, resulting in the advantage that the spacing between the threaded members in the central axial direction of the liquid flow path can be made closer, resulting in a compact liquid treatment nozzle with excellent cavitation generation efficiency. This effect is particularly noticeable when the distance between adjacent thread arrangement surfaces (flush thread assemblies) is kept to no more than twice the nominal thread diameter. Furthermore, when using a threaded member with a head larger in diameter than the stem, the spacing between the thread arrangement surfaces (flush thread assemblies) is set to be larger than the outer diameter of the head.

[0039] For example, when a configuration is adopted in which the same number of screw members (three or more) on each of adjacent screw arrangement surfaces are arranged at equal angular intervals around the central axis so that their legs are aligned along the radial direction of the cross section of the liquid flow path, it is advisable to determine that the arrangement angle phases of the screw members around the central axis are consistent on adjacent screw arrangement surfaces. In this way, the screw members on multiple screw arrangement surfaces are connected in a wall-like manner in the central axis direction, the cross section of the flow path is divided and partitioned by this wall-like thread row, and no other screw members are present within these partitioned areas, thereby significantly reducing the collision resistance of the liquid despite the large number of screws arranged. Furthermore, the thread roots of each screw member are densely arranged on the inner surface of the area partitioned by the wall-like thread row, dramatically increasing cavitation efficiency.

[0040] On the other hand, the legs of the threaded members on adjacent threaded surfaces can be positioned so that their longitudinal directions intersect with each other when projected onto a plane. In this configuration, although the loss due to collisions between individual threaded members and the liquid flow as the liquid passes through multiple surface-threaded sets is somewhat greater, the effect of agitating the liquid due to the turbulence generated by the collisions is more pronounced. For example, if a mixed flow of gas (one or more selected from air, oxygen, carbon dioxide, nitrogen, hydrogen, ozone, etc.) and liquid (water, cooking oil, liquid fossil fuels such as gasoline or diesel, alcohol, etc.) is supplied to the liquid treatment nozzle of the above configuration, the efficiency of dissolving the gas into the liquid can be improved by the above-mentioned agitation effect. It can also be effectively used to agitate and mix liquids with low mutual solubility (e.g., a water-based liquid with a low hydrophilic organic liquid) to form an emulsion.

[0041] In the above configuration, the spacing between the threaded surfaces in the direction of the central axis is preferably set to at least 2.0 times the nominal thread diameter of the threaded member. This reduces pressure loss when liquid flows through multiple threaded sets. The spacing between the threaded surfaces is more preferably set to at least 4.0 times the nominal thread diameter.

[0042] For example, when an equal number of screw members (three or more) are arranged at equal angular intervals around the central axis on each of adjacent screw arrangement surfaces so that the legs are aligned along the cross-sectional radial direction of the liquid flow path, in order to adopt the above configuration, the arrangement angle phases of the screw members around the central axis will be determined to be shifted from each other on adjacent screw arrangement surfaces. [Effects of the Invention]

[0043] The details of the operation and effects of the present invention have already been described in the section "Means for Solving the Problems," and will not be repeated here. [Brief explanation of the drawings]

[0044] [Figure 1] 1 is a perspective view showing an example of incorporating the liquid treatment nozzle of the present invention into water supply piping. [Figure 2]1A and 1B are a front view and a cross-sectional view of a liquid processing nozzle according to a first embodiment of the present invention. [Figure 3] FIG. 3 is a front cross-sectional view of a cavitation core used in the liquid treatment nozzle of FIG. 2. [Figure 4A] FIG. 10 is an axial cross-sectional view showing the layout of the screw members on the first screw arrangement surface of the cavitation core. [Figure 4B] FIG. 10 is an axial cross-sectional view showing the layout of the screw members on the second screw arrangement surface of the cavitation core. [Figure 5A] 4B is an enlarged axial cross-sectional view showing a main part of FIG. 4A. [Figure 5B] FIG. 4 is a conceptual diagram showing a modified example in which all the surface threads of the cavitation core in FIG. 3 are arranged in phase. [Figure 6A] 10A and 10B are axial cross-sectional views showing an example of a screw mounting hole and an example of an arrangement of a screw member within the screw mounting hole. [Figure 6B] 6B is an enlarged axial cross-sectional view showing the vicinity of the male thread portion of the screw member in FIG. 6A. [Figure 7A] FIG. 6B is a first explanatory view showing a step of inserting a screw into the screw insertion hole of FIG. 6A. [Figure 7B] An explanatory diagram following FIG. 7A. [Figure 8] 1 is an enlarged axial cross-sectional view showing a first example of an arrangement of a screw member near a head portion within a screw mounting hole. FIG. [Figure 9] FIG. 10 is an enlarged axial cross-sectional view of the second example. [Figure 10] FIG. 10 is an enlarged axial cross-sectional view of the third example. [Figure 11] 3 is an enlarged front cross-sectional view showing a core pressing portion of the liquid treatment nozzle of FIG. 2. [Figure 12] FIG. [Figure 13] 2A to 2C are diagrams illustrating the process of assembling a liquid processing nozzle to the piping system of FIG. 1. [Figure 14] 3A and 3B are diagrams showing the liquid processing nozzle of FIG. 2 mounted in a piping system in a forward direction and a reverse direction, respectively. [Figure 15] A cross-sectional view showing an example of a screw mounting hole of a core body used in a liquid processing nozzle according to embodiment 2 of the present invention. [Figure 16] FIG. 16 is an explanatory diagram of the operation of the screw mounting hole in FIG. 15 . [Figure 17] 10A and 10B are a front view, a front cross-sectional view, and a side view of a liquid processing nozzle according to a third embodiment of the present invention. [Figure 18] 18 is a plan view of a core plate used in the liquid treatment nozzle of FIG. 17. [Figure 19] 18 is a cross-sectional front view of a multi-core assembly incorporated into the liquid processing nozzle of FIG. 17. [Figure 20] A plan view of a core plate when the number of cavitation cores assembled is three, and a side view of a liquid treatment nozzle using the same. [Figure 21] 10A and 10B are a front view and a front cross-sectional view of a liquid processing nozzle according to a fourth embodiment of the present invention. [Figure 22] FIG. 10 is a front cross-sectional view of a liquid processing nozzle according to a fifth embodiment of the present invention. [Figure 23] 10A and 10B are a front view and a front cross-sectional view of a liquid processing nozzle according to a sixth embodiment of the present invention. [Figure 24] FIG. 10 is a front cross-sectional view of a liquid processing nozzle according to a seventh embodiment of the present invention. [Figure 25A] 25 is an axial cross-sectional view showing an example of an arrangement of a screw member in a screw mounting hole in the liquid processing nozzle of FIG. 24. [Figure 25B] 25B is an enlarged axial cross-sectional view showing the vicinity of the male thread portion of the screw member in FIG. 25A. [Figure 26] 25 is a front cross-sectional view of the essential parts of the liquid treatment nozzle of FIG. 24, in which four sets of threaded joints with the layout of FIG. 4A are arranged in the same phase in the central axis direction. [Figure 27] FIG. 10 is a front cross-sectional view of the essential parts of eight sets of liquid processing nozzles. [Figure 28] A front cross-sectional view of the main part of the liquid processing nozzle of Figure 24, in which one of the surface thread sets has the layout of Figure 4B. [Figure 29] A front cross-sectional view of the main part of a liquid processing nozzle in which the surface screw set in the structure of Figure 28 is divided into pairs of screw members that are perpendicular to each other and are arranged with each member shifted in position in the central axis direction. [Figure 30]A front cross-sectional view of the main part of a liquid treatment nozzle in which two pairs of threaded joints similar to those in the liquid treatment nozzle of Figure 28 are arranged in the central axis direction. [Figure 31] 1 is a front cross-sectional view showing an embodiment of a liquid processing nozzle having a gas introduction mechanism provided in a cavitation treatment unit. [Figure 32] An axial cross-sectional view of the main part of a liquid processing nozzle in which a surface thread assembly is composed of three screw members. [Figure 33] An axial cross-sectional view of the main part of a liquid processing nozzle in which a surface thread assembly is composed of eight screw members. [Figure 34] This is an axial cross-sectional view of the main part of a liquid processing nozzle in which a surface thread assembly is constructed using four screw members in a manner that does not form a center gap. [Figure 35] A front cross-sectional view of the main part of a liquid processing nozzle in which two sets of the face thread sets of Figure 34 are arranged in the central axis direction. [Figure 36] 10 is a graph showing the relationship between the area of ​​the liquid flow region and the flow rate when water is passed through a liquid treatment nozzle having four screw members arranged in a cross shape at a constant hydrodynamic pressure. [Figure 37] A graph comparing the cross-sectional flow velocity distribution of a liquid processing nozzle with four screw members arranged in a cross shape, with a nozzle with a cross-sectional inner diameter of 4.2 mm and a nozzle with a cross-sectional inner diameter of 3.5 mm and one and two face thread sets. [Figure 38] A graph showing the relationship between the dynamic water pressure and flow rate of various liquid treatment nozzles, each arranged with the threaded assembly rotated alternately by 45°, along with the results for liquid treatment nozzles of different shapes. [Figure 39] A graph showing the relationship between the dynamic water pressure and flow rate of various liquid treatment nozzles in which multiple thread sets are arranged in an overlapping phase relationship, along with the results for a liquid treatment nozzle in which two sets of thread sets are arranged, rotated 45° from each other. [Figure 40] FIG. 1 is a diagram showing the structure of an apparatus for evaluating the slimy soil removal capability of treated water. [Figure 41] FIG. 1 is an axial cross-sectional view of the main part of a liquid processing nozzle (reference nozzle) with two throttle holes. [Figure 42] FIG. 2 is a diagram illustrating the dimensional relationship between the various parts of the liquid processing nozzle used in the experimental example. [Figure 43]Schematic diagram of the test equipment used for the water flow test. DETAILED DESCRIPTION OF THE INVENTION

[0045] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. (Embodiment 1) FIG. 1 is a perspective view showing an example of a water supply piping system incorporating a liquid treatment nozzle of the present invention. In this water supply piping system 1200, a cold water supply section 1203 directly connected to a water supply system and a hot water supply section 1204 connected to a water heater (not shown) are each connected to a hot and cold water mixer 1201 via a stop valve 1211 and piping systems 1205 and 1206. The hot and cold water mixer 1201 is of a well-known configuration, mixing cold water from the cold water supply section 1203 and hot water from the hot water supply section 1204 at a mixing ratio and flow rate according to the operating state of a lever 1202, and discharging the mixed water from an outlet 1201. The piping systems 1205 and 1206 are both identical in configuration, and a liquid treatment nozzle 100 according to an embodiment of the present invention is incorporated between the outlet-side joint (male thread joint 1212 (FIG. 13) in this embodiment) of the stop valve 1211 and a flexible water supply pipe 1213. The liquid treatment nozzle 100 may be provided on either the cold water supply part 1203 or the hot water supply part 1204, for example, only on the cold water supply part 1203 side.

[0046] FIG. 2 shows an enlarged view of the liquid treatment nozzle, which includes a nozzle casing 50. In the direction O of liquid flow through the liquid treatment nozzle 100, the side where one of the liquid inlet and liquid outlet of the nozzle casing 50 is located is designated as the first side (or front end, on the left side in FIG. 2), and the side where the other is located is designated as the second side (or rear end, on the right side in FIG. 2). The nozzle casing 50 comprises a casing body 50B constituting the first side and a core pressing portion 50A constituting the second side, both of which are made of metal (e.g., a copper alloy such as brass (which may be coated with a plating layer of chromium or nickel, etc.), or an iron-based material such as stainless steel). The liquid treatment nozzle 100 is capable of flowing tap water as a liquid in both directions. For example, when water flows in the forward direction, the second-side opening 55 functions as an inlet-side opening and the first-side opening 54 functions as an outlet-side opening, and vice versa when water flows in the reverse direction. In this embodiment, the side of the nozzle casing 50 including the first side opening 54 is configured as a cylindrical casing main body 50B, and the side including the second side opening 55 is configured as a core pressing portion 50A.

[0047] The casing body 50B has a storage passage portion 56 formed in a manner that opens into a core insertion port 50p on its second side end face, and the second side end portion of the casing body 50 extends beyond the second side end face of the cavitation core 1 inserted into the storage passage portion 56, and an assembly female thread portion 50g is formed on the inner peripheral surface of the second side end portion. In addition, a first side flow path portion 50u that forms part of the liquid flow path 3 is formed penetrating the first side end portion of the casing body 50B, with one end in the axial direction opening as a first side opening portion 54 and the other end communicating with the storage passage portion 56.

[0048] On the other hand, an assembly male thread portion 50d that screws into an assembly female thread portion 50g of the casing body 50B is formed on the outer peripheral surface of the first side end of the core holding portion 50A, and an O-ring 50e is fitted at the base end position of the assembly male thread portion 50d. In addition, a second side flow path portion 50v that forms part of the liquid flow path 3 is formed in a manner that penetrates the core holding portion 50A in the axial direction, and a second side opening portion 55 is formed in the second side end surface of the core holding portion 50A.

[0049] A flange portion 50f protruding radially outward is formed on the outer peripheral surface of the core holding portion 50A. The first end face of the flange portion 50f abuts against the second end face of the casing body 50B, thereby restricting the relative threading amount of the assembly male thread portion 50d relative to the assembly female thread portion 50g so as to prevent excessive compression of the O-ring 50e. The outer peripheral surface of the flange portion 50f is also used as an engagement surface for a tool or jig when threading and fastening the core holding portion 50A to the casing body 50B during assembly. By threading and fastening the assembly male thread portion 50d to the assembly female thread portion 50g, the core holding portion 50A abuts its first end face (in this embodiment, the bottom surface of the counterbore 50n) against the second end face of the cavitation core 1, thereby preventing it from coming off. On the other hand, the first side end face of the cavitation core 1 is abutted against the outer peripheral edge of the first side end of the accommodation passage portion 56.

[0050] A nozzle-side threaded joint 51 is formed at the first end of the casing body 50B, and threads into a first threaded joint 1213a (FIG. 13) of the piping system. A cap nut 50C is rotatably fitted to the second end of the core retainer 50A, and threads into the male thread of the second threaded joint 1212 (FIG. 13) of the piping system. The outer peripheral surface of the cap nut 50C has a hexagonal tool engagement surface 53. FIG. 11 shows an enlarged view of the core retainer 50A and the cap nut 50C. The outer peripheral surface of the second end of the core retainer 50A is cylindrical, and a groove 50k is formed circumferentially at its front end, into which a metal snap ring 58 is fitted. A circumferential flange 50r protrudes from the inner peripheral edge of the first end of the cap nut 50C.

[0051] The inner diameter of the flange portion 50r is larger than the outer diameter of the second end of the core holding portion 50A and smaller than the outer diameter of the snap ring 58 fitted into the groove 50k. The second end of the core holding portion 50A is inserted into the inside of the flange portion 50r of the cap nut 50C, and in this state, the snap ring 58 is attached to the inside of the core holding portion 50A. Next, the cap nut 50C is elastically expanded in diameter by a jig (not shown), while the attached snap ring 58 is pressed axially toward the groove 50k. The snap ring 58 is then fitted into the groove 50k and the cap nut 50C is elastically returned to its original position. As a result, the cap nut 50C is fitted to the core holding portion 50A so as to be rotatable relative to the axis while being prevented from coming off in the axial direction by the snap ring 58.

[0052] 2, a tool engagement portion 57 having at least one pair of parallel surfaces is formed on the outer peripheral surface of the casing body 50B to engage with a fastening tool used when assembling the liquid processing nozzle 100 to a piping system. In this embodiment, the tool engagement portion 57 is formed as a hexagonal portion having three parallel portions on the outer peripheral surface of the first side end of the casing body 50B.

[0053] In this embodiment, the nozzle-side threaded joint 51 formed at the first end of the casing body 50B is formed as a male threaded portion. There are no particular restrictions on the dimensions of the male threaded portion of the nozzle-side threaded joint 51 and the dimensions of the female threaded portion 52 of the cap nut 50C, but in Figure 2, both are sized to conform to the G1 / 2 pipe parallel thread standard. A plate-shaped seal ring 50s is attached to the inside of the cap nut 50C.

[0054] Next, a liquid flow path 9A is formed axially penetrating the core body 1M of the cavitation core 1. The cavitation core 1 is inserted axially into the nozzle casing 50 so that the outer peripheral surface side is press-fitted or loose-fitted into the inner peripheral surface of the housing passage portion 56, in a positional relationship such that liquid supplied from one of the first side opening 54 and the second side opening 55 can pass through the liquid flow path 9A and flow out from the other. Specifically, the outer peripheral surface of the core body 1M is cylindrical, and it is inserted into the housing passage portion 56 from the core insertion port 50p.

[0055] FIG. 3 is an enlarged cross-sectional view of the cavitation core 1, and FIGS. 4A and 4B are axial cross-sectional views. A screw attachment hole 19 is formed penetrating from the outer peripheral surface of the core body 1M toward the inner peripheral surface of the liquid flow path 9A. The head 10h and the base end of the leg 10f of the screw member 10 are held within the screw attachment hole 19 of the core body 1M, while the tip end of the leg 10f protrudes from the inner surface of the liquid flow path 9A, forming a cavitation treatment section CV. Multiple screw attachment holes 19 are formed in the core body 1M, and a screw member 10 is attached to each of them. In the cavitation treatment section CV, as the liquid comes into contact with the male thread formed on the leg 10f, the liquid accelerates in the thread root, causing the dissolved gas to precipitate out in a supersaturated state due to the decompression effect.

[0056] The material of the core body 1M is a resin such as ABS, nylon, polycarbonate, polyacetal, or PTFE (polytetrafluoroethylene), but it can also be a metal such as stainless steel or brass, or a ceramic such as alumina, and is selected appropriately depending on the application. The material of the screw member 10 is, for example, stainless steel, but depending on the application, more corrosion-resistant heat-resistant alloys such as titanium, Hastelloy, or Inconel (all registered trademarks) can also be used. If wear resistance is an issue, ceramic materials such as quartz or alumina can also be used. Quartz is particularly suitable for applications where metal contamination is unacceptable (such as semiconductor manufacturing), and in this case, the resin cavitation core 1 should be made of, for example, PTFE.

[0057] 6A is an enlarged axial cross-sectional view showing the screw attachment hole 19 of the core body 1M and the arrangement of the screw member 10 relative to the screw attachment hole 19, and FIG. 6B is a further enlarged view showing the vicinity of the male thread portion 10mt. The screw attachment hole 19 formed in the core body 1M is provided with a leg insertion portion 19f for inserting and holding the base end side of the leg portion 10f of the screw member 10, and a head accommodating portion 19h which is integrally formed with the leg insertion portion 19f in a manner forming an opening on the outer peripheral surface side of the core body 1M, is formed to have a larger diameter than the leg insertion portion 19f, and accommodates the head. When the outer diameter of the male thread portion 10mt formed on the outer peripheral surface of the leg insertion portion 19f within the leg insertion portion 19f is md, and the thread height of the male thread portion 10mt is mtd, the inner diameter hd2 of the leg insertion portion 19f is md-mtd≦hd2 <md As shown in Fig. 6A, the leg portion 10f of the screw member 10 is screwed into the leg insertion portion 19f of the core body 1M in a self-tapping manner. Reference numeral 10e denotes a tool engagement recess for engaging a tool such as a screwdriver.

[0058] As shown in FIG. 8, when the thickness of the head of the screw member 10 is ht, the depth of the head accommodating portion 19h is determined so that the distance between the inner peripheral surface 56P of the accommodation passage portion 56 and the top surface of the head 10h is 0.5ht or less. In FIG. 8, a small gap GP1 (e.g., 0.15 mm or less) is formed between the inner peripheral surface 56P of the accommodation passage portion 56 and the outer peripheral surface 1P of the core body 1M. Meanwhile, the top surface of the head 10h protrudes from the opening of the head accommodating portion 19h by a height corresponding to the gap GP1, so that it is abutted against the inner peripheral surface 56P of the accommodation passage portion 56. In FIG. 8, a gap GP2 is formed between the outer peripheral surface of the head 10h of the screw member 10 and the inner peripheral surface of the head accommodating portion 19h.

[0059] With the above configuration, it is no longer necessary to deeply tap a female thread in advance in the leg insertion portion 19f of the core body 1M to thread the male thread portion 10mt of the screw member 10, thereby reducing the number of processing steps. Also, because the top surface of the head 10h of the screw member 10 is abutted against the inner peripheral surface of the accommodation passage portion 56, the position of the top surface of the head 10h is restricted by the inner peripheral surface of the accommodation passage portion 56, and there is no risk of rattle in the thrust direction of the screw member 10 inside the screw installation hole 19. Therefore, by circulating liquid through the liquid flow path 9A of the cavitation core 1, cavitation treatment can be carried out without any problems.

[0060] On the other hand, when the leg portions 10f of the screw member 10 are attached to the leg insertion portions 19f, the screw member 10 is screwed into the leg insertion portions 19f using a screwdriver or the like while self-tapping. As a result of the self-tapping, a shallow internal thread is carved into the inner surface of the leg insertion portions 19f. As a result, there is an advantage that the screw member 10 can be easily removed from the leg insertion portions 19f by rotating the screw member 10 in the opposite direction to that used for assembly, for example, when replacing a screw member 10 that has worn out due to repeated cavitation treatment, or when a screw member 10 with a different leg length has been incorrectly assembled into the leg insertion portions 19f.

[0061] As shown in the right of Figure 6B, the radial overlap length ftd between the internal thread portion 19ft formed by self-tapping and the external thread portion 10mt of the screw member 10 is a small value of 0.5 mtd or less (preferably 0.4 mtd or less, and more preferably 0.35 mtd or less). As shown in Figure 6A, the top surface position of the head portion 10h is restricted by the nozzle casing 50 (the inner peripheral surface of the accommodation passage portion 56 thereof), so there is no concern about excessive rattle in the thrust direction occurring in the screw member 10 inside the screw installation hole 19. Furthermore, although the overlap length is small, the screw member 10 and the leg insertion portion 19f are threadedly engaged, which has the advantage of making it less likely for the screw member 10 to fall out of the screw installation hole 19 of the core body 1M when the cavitation core 1 is installed in the accommodation passage portion 56.

[0062] 6A is configured as follows: The leg insertion portion 19f includes a first portion 19f1 that has a first inner diameter hd1 and an end portion that connects to the head accommodation portion 19h, and a second portion 19f2 that has a second inner diameter hd2 that is smaller than the first inner diameter hd1 and an end portion that connects to the liquid flow path 3. When the inner diameter of the head accommodation portion is hd3, the first inner diameter hd1 of the first portion 19f1 is md≦hd1 <hd3 As shown on the left side of FIG. 6B, the leg portion 10f of the screw member 10 is inserted into the first portion 19f1 in a loose fit state. On the other hand, the second inner diameter hd2 of the second portion 19f2 is set to be in the range of md-mtd≦hd2 <md As shown on the right side of FIG. 6B, the leg portion 10f of the screw member 10 is threaded into the second portion 19f2 in a self-tapping manner. The inner diameter hd2 of the second portion 19f2 is preferably md - 0.8 mtd or more, more preferably md - 0.7 mtd or more. If the inner diameter hd of the leg insertion portion is less than md - mtd, it becomes difficult to carve a female thread in the leg insertion portion by self-tapping. Furthermore, to ensure the effectiveness of carving a female thread, the inner diameter hd of the leg insertion portion should be set to md - 0.2 mtd or less, more preferably md - 0.4 mtd or less. In other words, the aforementioned overlap length ftd should be set to 0.1 mtd or more, more preferably 0.2 mtd or more. From the viewpoint of stably holding the leg portion 10f of the screw member 10 in a clearance fit with the first portion 19f1, it is preferable that hd1≦md+mtd, and more preferably hd1≦md+0.5mtd. Also, from the viewpoint of reliably abutting and fastening the seating surface of the screw head 10h against the stepped surface formed between the head accommodating portion 19h and the leg insertion portion 19f, it is preferable that hd1≦0.9hd3 (more preferably hd1≦0.8hd3) be satisfied.

[0063] If the screw member is a JIS-specified M1.4 normal pitch No. 0, Class 1 pan head machine screw, mtd is 0.1625 mm, thread pitch P is 0.3 mm, screw head outer diameter is φ2.0 mm, and height is 0.5 mm. In this embodiment, the M1.4 pan head machine screw is used, with hd1 = 1.4 mm and hd2 = 1.3 mm. The core body 1M has an outer diameter of φ14.8 mm, and the narrowed portion 9 has an inner diameter of φ8.0 mm. The leg insertion portion 19f has a head accommodating portion 19h with an inner diameter of φ2.1 mm and a depth of 0.8 mm. The leg insertion portion 19f has a first portion 19f1 with a depth of 1.7 mm (approximately 5.7 mm) and a second portion 19f2 with a depth of 0.9 mm (3 mm).

[0064] 7A and 7B , the process of assembling the screw member 10 to the core body 1M having the leg insertion portion 19f of the above-described structure will be described. First, as shown on the left side of FIG. 7A , the tip of the leg portion 10f of the screw member 10 is inserted into the first portion 19f1 of the leg insertion portion 19f. The leg portion 10f is stably held in the first portion 19f1 by a clearance fit. Next, as shown on the right side of FIG. 7A , the leg portion 10f is self-tapped into the second portion 19f2 in this state, allowing the tip of the leg portion 10f to bite into the second portion 19f2 very smoothly. Furthermore, by inserting the leg portion 10f into the first portion 19f1 by a clearance fit, the axis of the leg portion 10f can be aligned parallel to the axis of the second portion 19f2 using the first portion 19f1 as a guide. 7B, there is no risk of the leg 10f of the screw member 10 being screwed into the leg insertion portion 19f in an inclined state. When the pitch of the thread formed on the leg 10f is P, the length of the first portion 19f1 is preferably set to 3P or more. The length of the second portion 19f2 is preferably set to 1P or more and 10P or less.

[0065] As shown in FIG. 9, the core body 1M can also be press-fit into the accommodating passage 56. In this case, the outer peripheral surface of the core body 1M and the inner peripheral surface of the accommodating passage 56 are in close contact with each other, leaving no gap. The depth of the head accommodating portion 19h is determined so that the top surface of the head 10h of the screw member 10 is flush with the outer peripheral surface of the core body 1M. Alternatively, the outer peripheral surface of the head 10h of the screw member 10 may be in close contact with the inner peripheral surface of the head accommodating portion 19h. This configuration reduces the risk of the screw member 10 falling out of the screw mounting hole 19 of the core body 1M when the cavitation core 1 is attached to the accommodating passage 56. On the other hand, as shown in FIG. 10, when the thickness of the head is ht, a gap GP3 of 0.5ht or less may be formed between the inner peripheral surface 56P of the accommodating passage 56 and the top surface of the head 10h.

[0066] 3, the liquid flow path 3 of the core body 1M of the cavitation core 1 has a section including the midpoint G of the central axis of the liquid flow path 3 as a throttle section 9 in the form of a cylindrical surface, and the sections before and after the throttle section 9 of the liquid flow path 3 are a pair of expanded diameter sections 9B each having a larger diameter than the throttle section 9. The screw attachment hole 19 is disposed in the throttle section 9 together with the screw member 10, and a flow straightening member 63 is disposed inside each of the expanded diameter sections 9B in a form integrated with the core body 1M.

[0067] 12 shows the details of the flow straightening member 63, which is made by processing an elastic belt-shaped member such as steel into a zigzag shape so that peaks and valleys appear alternately along the folds in the direction of the short side, and then rolling it around an axis parallel to the short side to form a star-shaped cross section (hereinafter also referred to as star-shaped flow straightening member 63). As shown in FIG. 3, the star-shaped flow straightening member 63 is inserted with the direction of the short side coinciding with the axis of the housing passage portion 56, and the outer peripheral edge of the front end face is abutted against the stepped surface 9j on the side closer to the inlet-side opening 55.

[0068] Since the rectifying members 63 are provided not only on the downstream side but also on the upstream side of the cavitation core 1, a preliminary cavitation process (hereinafter referred to as preliminary cavitation process) is carried out when the liquid flows through the upstream rectifying members 63. The bubbles generated by this preliminary cavitation process can be finely pulverized by the subsequent stronger cavitation process when the liquid flows through the cavitation core 1. This, combined with the effect of the downstream rectifying members 63 suppressing the collision and coalescence of fine bubbles, can further increase the density of fine bubbles generated.

[0069] 12, separation flow is significantly formed at the edge of the metal elastic band member, which increases the amount of bubbles generated by the preliminary cavitation process upstream of the cavitation core 1, further increasing the density of generated microbubbles. However, the configuration of the flow straightening member 63 is not limited to this, and it may be, for example, a cylindrical member having multiple lotus-root-shaped pores formed through it in the axial direction, arranged so that the axis is parallel to the liquid flow direction.

[0070] Returning to FIG. 3 , the inner peripheral surface of the expanded diameter portion 9B is a cylindrical surface with a larger diameter than the constricted diameter portion 9 and is connected to the constricted diameter portion 9 via a stepped surface 9j. The star-shaped airflow control member 63, which is formed to have a larger diameter than the inner diameter of the expanded diameter portion 9B in its free state, is press-fitted into the expanded diameter portion 9B while elastically reducing its diameter in the radial direction relative to the axis. As a result, the star-shaped airflow control member 63 is integrated with the core body 1M in such a way that its outer peripheral surface is gripped by the inner peripheral surface of the expanded diameter portion 9B due to an elastic restoring force in the radial direction with its front end abutting the stepped surface 9j. This makes it less likely for the star-shaped airflow control member 63 to fall off from the core body 1M, thereby stabilizing the process of attaching the assembly of the airflow control member 63 and the core body 1M to the nozzle casing 50.

[0071] For example, the liquid treatment nozzle 100 is incorporated into the water supply piping system 1200 of Fig. 1 in the following procedure. That is, as shown on the left side of Fig. 13, the nut joint 1213a (first screw joint 1213a: female thread) of the flexible water supply piping 1213 directly connected to the stop valve 1211 is loosened, and the flexible piping 1213 is deformed to create space for nozzle installation between it and the joint part 1212 (second screw joint 1212: male thread) on the stop valve 1211 side. Next, the cap nut 50C (female thread) of the liquid treatment nozzle 100 is screwed and fastened to the second screw joint 1212. Next, the flexible piping 1213 is deformed again, and the nut joint 1213a is aligned with the nozzle side screw joint part 51 (male thread) of the liquid treatment nozzle 100 and screwed and fastened, thereby completing the installation. The liquid inlet side of the liquid treatment nozzle 100 is the lower side in Figure 13, i.e., the second side (right side) in Figure 2, and the outlet side is the upper side in Figure 13, i.e., the first side (left side) in Figure 2 (hereinafter, this will be referred to as the "forward direction"). However, depending on the construction situation at the site, the type of threaded joint of the piping system to which the liquid treatment nozzle 100 is to be assembled may be the opposite to that in Figure 13 (hereinafter, this will be referred to as the "reverse direction"). In such cases, the liquid treatment nozzle 100 must be assembled to the piping system upside down compared to that in Figure 13.

[0072] When the cavitation core 1 having the structure shown in FIG. 3 is used, the flow pattern of the liquid to the liquid processing nozzle 100 is the flow straightening member 63 → cavitation core 1 → flow straightening member 63, regardless of whether the liquid processing nozzle 100 is installed in the piping system in the forward direction shown on the left in FIG. 14 or in the reverse direction shown on the right in FIG. 14. As a result, the flow straightening member 63 can function as intended regardless of whether the liquid processing nozzle 100 is installed in the piping system in the forward or reverse direction. This significantly improves the flexibility of the liquid processing nozzle 100 in terms of the installation direction to the piping system. Furthermore, because the flow straightening member 63 is integrally installed in the expanded diameter portion 9B of the core body 1M, the flow straightening member 63 and the core body 1M can be installed together as an integrated assembly in the nozzle casing 50 during assembly of the liquid processing nozzle 100. As a result, the assembly process of the liquid processing nozzle 100 can be simplified.

[0073] Next, the structure of the cavitation treatment device CV of the liquid processing nozzle 100 will be described in detail. The screw member 10 used has a thread pitch and a thread root depth of 0.10 mm or more and 0.40 mm or less, and a nominal thread diameter M of 1.0 mm or more and 2.0 mm or less. In this embodiment, a JIS No. 0, Class 1 pan head machine screw is used as the screw member 10. The cavitation treatment device CV has multiple imaginary screw arrangement surfaces perpendicular to the central axis O of the liquid flow path 3 along the central axis O, five surfaces LP1 to LP5 in FIG. 3. The screw members 10 are arranged so that the longitudinal direction of their legs is aligned with each of the screw arrangement surfaces LP1 to LP5. The total number of screw members 10 is 20 (i.e., 8 or more), with two or more screw arrangement surfaces distributed to each of the screw arrangement surfaces LP1 to LP5, four in FIG. 3.

[0074] The screw members 10 are arranged on each of the screw arrangement surfaces LP1 to LP5 according to the layouts shown in FIGS. 4A and 4B. Specifically, in each layout, the four screw members 10 on each of the screw arrangement surfaces LP1 to LP5 form a surface-threaded set arranged in a cross shape perpendicular to one another. Each screw member 10 is inserted radially from the outer circumferential surface of the core body 1M into a leg insertion portion 19f of a screw installation hole 19 formed in the core body 1M so that the leg tip protrudes into the throttled portion 9. FIG. 5A shows a further enlarged view of the inside of the throttled portion 9, with a main flow region 21 formed between the screw member 10 and the inner circumferential surface of the throttled portion 9. In addition, in each throttled portion 9, a liquid flow gap 15 is formed at the center of the cross formed by the four screw members 10. The tip surfaces of the four screw members 10 forming the liquid flow gap 15 are formed flat, and the liquid flow gap 15 is formed in a square shape when projected onto a plane perpendicular to the central axis.

[0075] In FIG. 5A, the area of ​​the liquid flow region in each of the screw arrangement surfaces LP1 to LP5 (hereinafter also referred to as the total flow cross-sectional area) a is calculated by multiplying the total area inside the outer periphery of the projected area of ​​the liquid flow path (here, the area of ​​the circular axial cross section of the throttle portion 9 in FIG. 2: πd 2 / 4)) is S1, and the projected area of ​​the screw member 10 (four screw members) is S2, a=S1-S2 (unit: mm 2 ) In this embodiment, the total area of ​​the main flow region 21 and the liquid flow gap 15 corresponds to the total flow cross-sectional area a. As shown in FIG. 2, the opening diameters of the inlet-side opening 55 and the outlet-side opening 54 are larger than the inner diameter of the throttle section 9. That is, the opening cross-sectional areas of the inlet-side opening 55 and the outlet-side opening 54 are set larger than the total flow cross-sectional area a. And, in each of the screw arrangement surfaces LP1 to LP5, the total flow cross-sectional area a is 3.8 mm 2 The in-plane flow area ratio, which is defined as the ratio of the liquid flow area to the total cross-sectional area S1 of the liquid flow path (that is, a / S1×100(%)), is ensured to be 40% or more.

[0076] In FIG. 5A, the depth h of the valleys appearing on the projected outline of the screw member 10 is ensured to be 0.1 mm or more. When a circle drawn with a radius corresponding to 70% of the distance to the inner peripheral edge of the liquid flow path and centered on the projection point of the central axis O is defined as a reference circle C70, the number of valley points (indicated by ○) representing the lowest positions of the valleys that are located inside the reference circle C70, i.e., the number of valley points that are located within 70% of the radius of the liquid flow path 3 from the central axis O of the liquid flow path 3 when projected onto a plane perpendicular to the central axis O, is defined as the 70% valley point number N70. The value obtained by summing up the 70% valley point number N70 values ​​for all thread arrangement surfaces and dividing this value by the total cross-sectional area S1 of the liquid flow path 3 (throttle section 9) is defined as the 70% valley point area density. In the liquid processing nozzle 100 of FIG. 2, the value of the 70% valley point area density is 1.6 / mm. 2 More than this is guaranteed.

[0077] The surface thread assemblies shown in Figures 4A and 4B are geometrically equivalent, but when assembled to the core body 1M, the angular phases around the central axis are shifted by 45° from each other. In the configuration of the cavitation core 1 in Figure 3, the first-type surface thread assemblies in Figure 4A and the second-type surface thread assemblies in Figure 4B are alternately arranged on the thread arrangement surfaces LP1 to LP5, thereby forming a symmetrical thread layout. In addition, the surface spacing dp between adjacent thread arrangement surfaces LP1 to LP5 is set to, for example, 1.05dh or more and 2M or less, where dh is the outer diameter of the head portion 10h in Figure 2 and M is the nominal thread diameter of the leg portion 10f.

[0078] 5B, the legs of the screw members 10 can also be arranged in a positional relationship where they overlap each other on adjacent screw arrangement surfaces LP1 to LP5 while aligning their longitudinal directions when projected onto a plane orthogonal to the central axis O. In Fig. 5B, the surface thread assemblies made up of four screw members 10 arranged in a cross shape as in Fig. 4A are arranged in a positional relationship where they overlap each other on the screw arrangement surfaces LP1 to LP5 (i.e., a positional relationship where the arrangement angle phases around the central axis of the cross-shaped surface thread assemblies coincide with each other: hereinafter, this arrangement will also be referred to as "in-phase arrangement").

[0079] As will be described later, a cavitation treatment unit in which multiple thread assemblies are arranged in phase, as in Figure 5B, has the advantage of being able to effectively suppress the increase in pressure loss during liquid flow when the number of threaded members is increased. On the other hand, a cavitation treatment unit in which thread assemblies with different angular phases around the central axis are alternately arranged, as in Figure 3, can achieve a 70% valley point area density equivalent to the configuration in Figure 5B, but when the surface spacing dp of the threaded surfaces LP1 to LP5 is the same as in the configuration in Figure 5B, the pressure loss during liquid flow becomes slightly larger. On the other hand, the turbulent agitation effect of the liquid is greater than that of the configuration in Figure 5B, making it more advantageous for purposes such as dissolving gas into liquid by supplying a multiphase flow.

[0080] The following describes the operation of the liquid treatment nozzle 100 in Figure 2 when, for example, the liquid outlet side is opened and water with dissolved air (for example, ordinary tap water: oxygen concentration at 20°C (room temperature) is about 8 ppm) is passed through as the liquid so that the dynamic pressure is about normal tap water pressure (for example, 0.077 MPa). As shown in Figure 5A, in the cavitation treatment unit, the water flow passes through a liquid flow area consisting of a main flow area 21 and a liquid flow gap 15 formed between the screw member 10 and the inner surface of the throttling section 9, while colliding with the screw member 10.

[0081] As the water passes over the outer circumferential surface of the leg of the screw member 10, a high-speed region is generated in the thread root (particularly at the root bottom) and a low-speed region is generated in the thread. The high-speed region in the thread root then becomes a negative pressure region according to Bernoulli's theorem, resulting in cavitation. Because the thread roots are formed in multiple turns around the outer periphery of the screw member, and eight or more screw members 10 are distributed among multiple thread arrangement surfaces LP1 to LP5, cavitation simultaneously occurs in multiple locations in the thread roots within the throttle section 9. When the water flow collides with the screw member 10, dissolved air is violently decompressed and precipitated in a boiling manner in the thread roots, causing intense friction and agitation of the water flow between the surface of the screw member 10 and the inner surface of the liquid flow path 3.

[0082] The cavitation core 1 in Figure 3 has an in-plane flow area ratio of 40% or more on each of the screw arrangement surfaces LP1 to LP5, and the total flow cross-sectional area is 3.8 mm 2 The above is ensured, and furthermore, the interval dp between adjacent thread arrangement surfaces LP1 to LP5 (surface thread sets) is ensured to be larger than the nominal thread diameter of the threaded member 10 used. This makes it possible to keep the increase in pressure loss of the nozzle extremely small even when multiple surface thread sets are arranged in a row in the direction of the central axis O. As a result, even though more threaded members than conventional ones are arranged in one liquid flow path 3, it is possible to sufficiently ensure the required flow velocity within the cross section. For example, in Patent Document 2, a flow rate of 1.1 pieces / mm 2 The 70% valley point area density, which was previously thought to be the limit, was increased to 1.6 counts / mm while maintaining sufficient flow velocity. 2 You can set it to a larger value than this.

[0083] In Patent Document 2, the inventors suggested that water subjected to cavitation treatment using the liquid treatment nozzle disclosed therein exhibits improved permeability into skin, hair, etc., and that the improved permeability effect becomes more pronounced as the 70% valley point density of the liquid treatment nozzle increases. Furthermore, the inventors also suggested that skin and hair are composed of proteins, which are polymers, and that the improved permeability of water at the molecular level into such polymer network structures cannot be explained solely by the effect of microbubbles in the water. For example, the inventors also suggested that microbubbles may be involved in the physical properties of water, particularly the collective (statistical) behavior of polar water molecules, thereby increasing the permeability of water. However, Patent Document 2 is silent on how the properties of the treated liquid are improved when cavitation treatment is performed using a nozzle with a 70% valley point area density that is increased to the above-mentioned large value.

[0084] When water subjected to cavitation treatment using the liquid treatment nozzle 1 is measured using, for example, a laser diffraction particle size analyzer, it can be confirmed that the water contains a large amount of nano-sized microbubbles with an average diameter of approximately 100 nm to 300 nm, as in Patent Document 2. As will be clear from the experimental results described below, the microbubbles of the above average diameter that can be detected using a laser diffraction particle size analyzer largely disappear if the water is stored in a tank or the like after cavitation treatment and left for several minutes, and become undetectable using a laser diffraction particle size analyzer with normal sensitivity. However, even in treated water after storage in which these microbubbles are no longer detectable, if a liquid treatment nozzle with an increased 70% valley point area density is used, the effects of cavitation treatment, such as improved permeability, can be achieved in the same way as in treated water immediately after passing through the nozzle in which microbubbles are detectable. Although the mechanism by which effects such as improved permeability are produced is currently under research, the inventors believe that a large number of stable bubble nuclei of less than 10 nm in size (which cannot be measured by existing methods such as laser diffraction / scattering and particle tracking analysis) are formed in the water when their growth stops due to instantaneous cavitation or when bubbles redissolve, and that these bubble nuclei improve the collective flow behavior of polarized water molecules.

[0085] (Embodiment 2) For example, in the cavitation core 1 of the liquid processing nozzle 100 of Figure 2, this can be achieved by replacing the screw mounting hole 19 from the configuration of Figure 6A to the configuration of Figure 15 (since the remaining configuration except for the structure of the screw mounting hole 19 is the same as that of embodiment 1, detailed explanation will be omitted).

[0086] 15 is composed of a first portion 19f1 that includes the end portion on the connection side with the head accommodation portion 19h and has a first inner diameter hd1, and a second portion 19f3 that includes the end portion on the connection side with the liquid flow path 3 and has a second inner diameter hd2 that is smaller than the first inner diameter hd1. When the inner diameter of the head accommodation portion is hd3, the first inner diameter hd1 of the first portion 19f1 is md≦hd1 <hd3 The leg portion 10f of the screw member 10 is inserted into the first portion 19f1 in a loose fit manner. On the other hand, the second inner diameter hd2 of the second portion 19f3 is set to be in the range of md-mtd≦hd2 <md When the pitch of the thread formed on the leg portion 10f is P, the length of the second portion 19f3 is set to be equal to or greater than 1P and equal to or less than 2P. The leg portion 10f of the screw member 10 is not self-tapping with respect to the second portion 19f3, but is press-fitted into the inner circumferential surface of the second portion 19f3 with the tip thereof protruding into the liquid flow path 3, as shown on the right side of FIG.

[0087] When the screw member 10 is attached to the leg insertion portion 19f, as shown on the left in Figure 16, the leg is first loosely fitted into the first portion 19f1, and then the screw member 10 is press-fitted axially (in the thrust direction) into the second portion 19f3. This allows the metal leg portion 10f to be attached to the core body 1M with the threads climbing over the resin inner peripheral surface of the second portion 19f3. It can be seen that this simplifies the process of assembling the screw member 10 to the core body 1M.

[0088] (Embodiment 3) In the liquid treatment nozzle 200 of Figure 17, multiple cavitation cores 1 are incorporated into the nozzle casing 50. A space is formed between the outer peripheral surface of the cavitation core 1 and the inner peripheral surface of the storage passage portion 56 of the nozzle casing 50. The following mainly focuses on the differences from the liquid treatment nozzle of embodiment 1, and conceptually common parts may be given the same reference numerals and detailed explanations may be omitted.

[0089] The nozzle casing 50 comprises a casing body 50B, a core pressing portion 50A, and a cap nut 50C rotatably fitted to the core pressing portion 50A. The configuration of the cavitation core 1 is the same as that shown in Figure 3, and two (multiple) cavitation cores 1, 1 are arranged parallel to each other in the axial direction in a storage passage portion 56 formed in the casing body 50B. The inner diameter of the storage passage portion 56 is set to be more than twice the outer diameter of the cavitation core 1. The casing body 50B has a tool engagement portion 257 consisting of a pair of parallel surfaces formed by cutting out a first side end of the outer circumferential surface in an offset manner.

[0090] The multiple cavitation cores 1 are integrated by fitting assembly plates 201 onto both end faces in an arrangement in which the central axes are parallel to each other, thereby forming a multi-core assembly 210. The multi-core assembly 210 is axially attached to the housing passage 56 of the casing main body 50B, and the outer peripheral edge of the first side end face of the core pressing portion 50A is in close liquid-tight contact with one of the assembly plates 201, 201 (upper side in the drawing), thereby preventing the multi-core assembly 210 from slipping out. In addition, the outer peripheral edge of the other side (lower side in the drawing) of the assembly plates 201, 201 is in close liquid-tight contact with the outer peripheral edge of the first side end of the housing passage 56.

[0091] FIG. 18 is a plan view of the assembly plate 201, on which multiple core fitting portions 213 are formed. Each core fitting portion 213 consists of a circular counterbore 211 and a liquid circulation hole 212 with a diameter smaller than that of the counterbore 211. As shown in FIG. 3, the outer peripheral edge of each end face of the core body 1M is cut out in a stepped pattern to form a circumferential fitting groove 1G, inside which a small-diameter portion 1C is formed. As shown in FIG. 19, each cavitation core 1 of the multi-core assembly 210 is fitted into the counterbore 211 of the corresponding assembly plate 210 at the small-diameter portions 1C on both ends. The liquid circulation holes 212 of the assembly plate 201 are set to an inner diameter corresponding to the expanded-diameter portion 9B of the cavitation cores 1, 1.

[0092] As shown in Figure 17, the first side flow path portion 50u of the casing main body 50B and the second side flow path portion 50v of the core pressing portion 50A both have tapered surfaces 50ut, 50vt on the inner surfaces facing the corresponding assembly plate 201 that continuously expand in diameter toward the assembly plate 210 to have dimensions that include all of the liquid circulation holes 212.

[0093] In the liquid processing nozzle 200, for example, liquid is flowed into the second-side flow path portion 50v from the second-side opening 55, whereupon it flows through each cavitation core 1 via the expanded diameter portion 50vt, joins at the expanded diameter portion 50ut, and then flows out of the first-side opening 54 via the first-side flow path portion 50u. This allows for cavitation treatment of a larger flow rate of liquid than the liquid processing nozzle 100 of embodiment 1. In this embodiment, the dimensions of the male thread portion of the nozzle-side threaded joint portion 51 and the female thread portion 52 of the cap nut 50C are both G3 / 4 dimensions of the pipe parallel thread standard.

[0094] The number of cavitation cores 1 incorporated into the multi-core assembly 210 is not limited to two, and for example, as shown in FIG. 20, three cavitation cores 1 can be incorporated.

[0095] Hereinafter, an embodiment of a liquid treatment nozzle in which an additional function part is added to a casing main body will be described. (Embodiment 4) 21, the nozzle casing 50 is made up of a flow path adjustment valve 50D, which constitutes an additional functional part, a casing main body 50B', and a core pressing part 50A, and a cap nut 50C is rotatably fitted to the core pressing part 50A. The following mainly focuses on the differences from the liquid processing nozzle of embodiment 1 (conceptually common parts may be given the same reference numerals and detailed explanations may be omitted).

[0096] The flow path adjustment valve 50D includes a valve casing 69, and a female thread portion 71 is formed on the inner peripheral surface of the second side end portion thereof. Furthermore, a male thread portion 51' is formed on the outer peripheral surface of the first side end portion of the casing main body 50B', and is threadedly engaged with the female thread portion 71 of the flow path adjustment valve 50D via a seal ring 70. A first side flow path portion 50u1 formed in the casing main body 50B' communicates with a main valve flow path portion 50u2 formed through the valve casing 69. Furthermore, the nozzle side threaded joint portion 51 is formed as a male thread portion on the first side end portion of the valve casing 69.

[0097] A valve element holder 74 is incorporated into the main valve flow path 50u2 to hold the ball valve element 72 rotatably about an operating axis HA. A valve element flow path 80 is formed in the ball valve element 72, and an operating axis HA is set in a direction perpendicular to the axis of the valve flow path 80. One end of an operating shaft 76 is coaxially connected to the ball valve element 72 with respect to the operating axis HA. An operating handle 78 is connected to the other end of the operating shaft 76 so as not to rotate relative to the operating shaft 76.

[0098] When the operating handle 78 is rotated around the operating axis HA, the ball valve element 72 rotates via the operating shaft portion 76. The overlapping area between the opening of the valve element flow path 80 formed in the ball valve element 72 and the flow path cross section of the main valve flow path portion 50u2 changes continuously according to the angular phase of the operating handle 78. This allows the effective flow path cross-sectional area of ​​the liquid processing nozzle 300 to be continuously switched, and ultimately the flow rate of the piping system in which the liquid processing nozzle 300 is incorporated can be easily adjusted by the flow path adjustment valve 50D. Note that the flow path adjustment valve 50D is not limited to the ball valve as described above, and may be configured, for example, as a stop valve that switches the flow path between two states: a fully closed state (blocked state) and a fully open state (open state).

[0099] (Embodiment 5) The liquid processing nozzle 400 of Figure 22 shows an example in which a branch pipe 31 for branching and circulating liquid from the liquid flow path is provided as an additional functional part. In the liquid processing nozzle 400, the nozzle casing 450 consists of a casing main body 50B', a core holding part 50A', and a cap nut 50C'. The cap nut 50C' is rotatably fitted to the first side end of the casing main body in a configuration similar to that of Figure 11. In addition, the nozzle side threaded joint part 51' is formed as a male thread part at the second side end of the core holding part 50A'. Below, differences from the liquid processing nozzle of embodiment 1 will be mainly explained (conceptually common parts may be given the same reference numerals and detailed explanations may be omitted).

[0100] The branch pipe 31 has a male thread 97m formed on the outer peripheral surface of one end thereof, and is coupled to the first-side flow path portion 50u of the casing body 50B' by threading it into a female thread 97f formed through the side wall portion of the casing body 50B' so as to communicate with the first-side flow path portion 50u of the casing body 50B'. Meanwhile, a valve hole 98 is formed through the side wall portion of the casing body 50B' on the opposite side of the central axis from the communication position of the branch pipe 31, and an adjustment valve (a butterfly valve in this embodiment) 99 for adjusting the amount of liquid distributed to the branch pipe 31 side is attached to the inside of the valve hole 98 via a seal ring 99c, facing the communication-side opening of the branch pipe 31.

[0101] On the other hand, a chemical liquid holding section 33 is provided at the opposite end of the branch pipe 31, which receives the inflow of liquid from the branch pipe 31 and dissolves the chemical liquid into the received liquid. The liquid in the branch pipe 31, from which the chemical liquid has been dissolved from the chemical liquid holding section 33, gradually flows out in a backflow manner from the end of the branch pipe 31 connected to the casing main body 50B' to the liquid flow path 3 side. The amount of liquid distributed and flowing out to the branch pipe 31 can be changed by changing the flow cross-sectional area of ​​the first-side flow path section 50u using the adjustment valve 99. The greater the amount of liquid distributed and flowing out to the branch pipe 31, the greater the amount of chemical liquid gradually released and flowing out from the liquid holding section 33 to the first-side flow path section 50u side. Such a liquid treatment nozzle 400 can be attached as a sanitizer to a pipe that supplies flushing water to a toilet bowl (e.g., a urinal), for example.

[0102] The chemical solution can be a cleaning solution for disinfecting bacteria and removing urinary stones (for example, well-known solutions of didecyldimonium chloride, benzalkonium chloride, polyhexamethylene biguanide, or dimethicone dissolved in water with a fragrance and a surfactant), which can disinfect the inner surface of the toilet bowl and remove urinary stones from the drain pipe. In the configuration of Figure 22, flushing water is supplied to the liquid treatment nozzle 400 from the second side opening 55 (left side of the drawing), and after being subjected to cavitation treatment in the cavitation core 1, it is mixed with the cleaning chemical solution from the branch pipe 31 and flows out from the first side opening 54 (right side of the drawing) toward the toilet bowl (not shown). The flushing water is given the effect of improving permeability due to cavitation, further improving its cleaning power for the toilet bowl. It is also possible to reduce the amount of chemical solution injected to maintain the same level of cleaning power.

[0103] (Embodiment 6) 23, the nozzle casing 550 is made up of a casing body 550B, a core holding portion 550A, and a cap nut 550C, and a tool engagement hole 550v is formed at the second side end of the core holding portion 550A, which forms part of the liquid flow path 3 and is for engaging an assembly tool used when screwing together the assembly male screw portion 50d of the core holding portion 550A with the assembly female screw portion 50g of the casing body 550B. The following mainly focuses on the differences from the liquid processing nozzle of embodiment 1, and conceptually common parts may be given the same reference numerals and detailed description thereof may be omitted.

[0104] The cap nut 550C is rotatably fitted to the second end of the core holding portion 550A. The flange portion 552 forming the first end of the cap nut 550C and the flange portion 551 forming the second end of the core holding portion 550A are directly engaged with each other, eliminating the snap ring 58 shown in FIG. 11 . In this embodiment, the tool engagement hole 550v has a hexagonal cross-sectional shape, allowing a hexagonal wrench to be used as a tool. This configuration allows the nozzle casing 550 to be assembled smoothly and easily by threading the assembly male thread portion 550d of the core holding portion 550A with the assembly female thread portion 550g of the casing main body 550B. Then, tools are engaged with the tool engagement portion 57 on the casing main body 550B and the tool engagement hole 550v of the core holding portion 550A and rotated relative to each other about the axis. Furthermore, after the assembly is completed, the tool engagement hole 550v of the core pressing portion 550A can be reused as part of the liquid flow path 3, which also contributes to simplifying the structure of the liquid processing nozzle 550.

[0105] (Embodiment 7) The liquid processing nozzle 600 in Figure 24 has an overall cylindrical appearance, with one liquid flow path 603 having a circular cross section formed therethrough in the direction of a central axis O. The liquid flow path 603 has an inlet opening 604 at one end (the right side of the drawing) and an outlet opening 605 at the other end, and a throttle section 609 having a smaller diameter than the inlet opening 604 and the outlet opening 605 is formed at a middle position in the flow direction, forming a partial section of the liquid flow path 603. The liquid flow path 603 has an inlet tapered section 606 on the inlet opening 604 side relative to the throttle section 609, and an outlet tapered section 607 on the outlet opening 605 side. A screw member 10 is attached to the throttle section 609 so that the tip of the leg protrudes into the flow path, forming a cavitation treatment section CV. The liquid to be treated is, for example, water (or an aqueous solution with a desired solute component dissolved therein as needed), but liquids other than water (for example, organic solvents such as alcohol, fossil fuels such as gasoline or diesel, cooking oil, etc.) may also be used.

[0106] The liquid processing nozzle 600 includes a nozzle casing 602 and a cavitation core 1. In this embodiment, the liquid processing nozzle 600 is made up of four main parts: the cavitation core 1, a casing body 602CA and a core holding portion 602CB that constitute the nozzle casing 602, and a tapered piece 602CP. The cavitation core 1 also includes a core body 1M and a screw member 10.

[0107] A casing body 602CA of the nozzle casing 602 has an accommodation passage portion 651 that is open at both ends in the liquid flow direction (the direction of the central axis O). Specifically, an inlet-side opening 604 is formed at a second end of the casing body 602CA, and a cap nut 616 is rotatably fitted thereto. An inlet-side tapered portion 606 is formed downstream of the inlet-side opening 604 and gradually reduces in diameter in the liquid flow direction. A cylindrical surface portion 609B having the same inner diameter as the outlet opening of the inlet-side tapered portion 606 is formed and connected to the outlet opening. This cylindrical surface portion 609B forms a part of the throttle portion 609. The accommodation passage portion 651 has a larger diameter than the cylindrical surface portion 609B and is connected to the cylindrical surface portion 609B by forming a stepped surface 652. A female screw portion 653 for connecting to a casing is formed on the downstream side of the accommodation passage portion 651 in the direction of liquid flow, with a stepped surface 652 and a larger diameter than the accommodation passage portion 651 .

[0108] Next, a liquid flow path 609A is formed through the core body 1M of the cavitation core 1, with a liquid inlet opening at one end face in the direction of the central axis O and a liquid outlet opening at the other end face, and the core body 1M is inserted in the direction of the central axis O so that its outer peripheral surface is press-fitted or loose-fitted into the inner peripheral surface of the accommodation passage portion 651, in a positional relationship such that liquid supplied toward the inlet side opening 604 of the nozzle casing 602 can flow out from the outlet side opening 605 via the liquid flow path 609A. Specifically, the core body 1M has a cylindrical outer peripheral surface, and is coaxially inserted into the accommodation passage portion 651 from the female thread portion 653 side.

[0109] The arrangement of the screw member 10 in the cavitation treatment section CV is conceptually almost the same as that shown in Fig. 4A. That is, in the cavitation treatment section CV, a plurality of imaginary screw arrangement surfaces perpendicular to the central axis O of the liquid flow path 3 are set along the central axis O, two surfaces LP1 and LP2 in Fig. 24, and the surface thread set in Fig. 4A is arranged in phase with the screw arrangement surfaces LP1 and LP2. Also, as shown in Fig. 25A, the inner diameter hd of the leg insertion portion 19f of the screw mounting hole 19 is md-mtd≦hd <md Therefore, as shown in Fig. 25B, the leg portion 10f of the screw member 10 is attached in a self-tapping manner over the entire section within the leg portion insertion portion 19f.

[0110] Returning to Figure 24, the tapered piece 602CP has a cylindrical outer peripheral surface and is inserted into the housing passage portion 651 in the direction of the central axis O, adjacent to the downstream side of the cavitation core 1. A first tapered portion 607A having openings at both ends in the liquid flow direction (the direction of the central axis O) is formed through the tapered piece 602CP. The first tapered portion 607A forms part of the upstream side of the outlet-side tapered portion 607, and its inlet-side opening is formed to have the same inner diameter as the liquid flow path 609A of the cavitation core 1 and is formed to gradually increase in diameter toward the outlet-side opening.

[0111] The core holding portion 602CB has a female thread joint 617 that forms the outlet-side opening 605. A second tapered portion 607B that forms the inlet-side opening of the core holding portion 602CB is formed upstream of this female thread joint 617. The second tapered portion 607B forms a part of the downstream side of the outlet-side tapered portion 607 and is formed so that its diameter gradually decreases toward the inlet-side opening, which has the same inner diameter as the outlet-side opening of the tapered piece 602CP. The upstream end portion where the inlet-side opening is located is tapered by a stepped surface 655, and its outer peripheral surface is formed with a male thread portion 656 that screws into the female thread portion 653 of the casing main body 602CA. The downstream end face of the tapered piece 602CP is restricted from moving downstream in the direction of the central axis O by the upstream end face of the core holding portion 602CB.

[0112] In the above configuration, the outlet-side tapered section 607 is formed so that its section length in the direction of liquid flow is longer than that of the inlet-side tapered section 606. By setting the section length of the outlet-side tapered section 607 to be this large, the formation of a swirling flow along the inner circumference of the tapered surface becomes prominent when the liquid flows through it. For example, even if the dissolved gas precipitated under reduced pressure in the cavitation core 1 grows into somewhat large bubbles, it can be finely pulverized by being entrained in the swirling flow along the outlet-side tapered section 607. Furthermore, when a soluble gas is introduced from the outside into the flowing liquid, as in the modified example shown in Figure 31 (described later), the dissolution efficiency of the soluble gas can be improved by entraining it in this swirling flow.

[0113] Furthermore, by dividing the outflow-side tapered portion 607 into a first tapered portion 607A of the tapered piece 602CP and a second tapered portion 607B of the core holding portion 602CB, for example, the axial insertion length of a cutting tool can be shortened when forming the outflow-side tapered portion 607 by cutting the inner surface, making processing much easier. Note that if it is desired to form an outflow-side tapered portion 607 with a longer section length, it is also possible to divide the tapered piece 602CP into two or more pieces.

[0114] The materials of the casing body 602CA, core pressing portion 602CB, tapered piece 602CP and core body 1M are resins such as ABS, nylon, polycarbonate, polyacetal, PTFE, etc., but may also be metals such as stainless steel or brass or ceramics such as alumina, and are selected appropriately depending on the application.

[0115] FIG. 31 is a cross-sectional view showing a modified example of the liquid processing nozzle 600, in which a gas introduction mechanism is provided. The casing body 602CA is formed with a gas introduction hole 626 that opens onto the outer peripheral surface of the casing body 602CA and communicates with the throttle section 609 upstream of the cavitation treatment section CV. The opening of the gas introduction hole 626 on the outer peripheral surface side of the casing body 602CA is formed with a female thread 629, to which a gas introduction joint (not shown) for connecting a gas supply pipe can be attached. The gas introduction hole 626 and the gas introduction joint constitute a gas introduction mechanism, and by connecting a gas supply pipe (not shown) to the gas introduction joint, the gas to be dissolved into the throttle section 609 can be easily introduced. For example, by connecting a gas supply pipe from an air compressor (not shown), air can be dissolved in the water to be treated. This ensures the amount of dissolved air necessary for cavitation, even in water lacking dissolved air.

[0116] Various modifications of the cavitation treatment unit will be described below, which can be applied to any of the above-described embodiments. FIG. 26 shows a configuration in which four sets of thread assemblies having the layout shown in FIG. 4A are arranged in the direction of the central axis O in the cavitation treatment device CV of the liquid processing nozzle 600 of FIG. 24. Specifically, four thread arrangement surfaces LP1 to LP4 are arranged in the direction of the central axis O with the same surface spacing dp as in FIG. 24, and the cross-shaped thread assemblies of FIG. 4A are arranged so as to overlap each other (i.e., in phase). In this case, 16 thread members 10 are distributed among the four thread arrangement surfaces LP1 to LP4. FIG. 27 shows an example of a cavitation treatment device CV in which the thread assemblies of FIG. 4A are arranged in phase with eight thread arrangement surfaces LP1 to LP8. In this case, 32 thread members 10 are distributed among the eight thread arrangement surfaces LP1 to LP8. The 70% valley point area density of each cavitation treatment device CV can be increased by two times in the configuration of FIG. 26 and four times in the configuration of FIG. 27 compared to the configuration of FIG. 24.

[0117] FIG. 28 shows an example of the cavitation treatment device CV of the liquid processing nozzle 600 of FIG. 24, in which the surface thread assemblies having the layout shown in FIG. 4A are provided on the thread arrangement surface LP1 and the surface thread assemblies having the layout shown in FIG. 4B are provided on the thread arrangement surface LP2. FIG. 29 shows an example of a cavitation treatment device CV in which the surface thread assemblies in the configuration of FIG. 28 are divided into pairs of thread members that are orthogonal to each other and are positioned at offset positions along the central axis O. Specifically, in FIG. 24, four thread members 10 were arranged on each of the thread arrangement surfaces LP1, LP1′ and LP2, LP2′, and in the configuration of FIG. 29, two thread members are distributed perpendicular to each other on two thread arrangement surfaces LP1, LP1′ and LP2, LP2′, which are separated by the nominal thread diameter M of the thread members 10. That is, this shows an example in which eight thread members 10 are distributed among four thread arrangement surfaces LP1, LP1′, LP2, LP2′. The distance between the thread placement surface LP1' and the thread placement surface LP2 is set to be larger (for example, about 1.5M to 2.0M) than the nominal thread diameter M. The 70% valley point area density in this configuration is equivalent to that of the configuration in FIG.

[0118] 30 shows an example of a cavitation treatment section CV in which the surface thread sets of the layout of FIG. 4A and the surface thread sets of the layout of FIG. 4B are alternately arranged in pairs on the four thread arrangement surfaces LP1 to LP4, for a total of four sets. In this example, 16 screw members 10 are distributed in groups of four on the four thread arrangement surfaces LP1 to LP4. The 70% valley point area density in this configuration is twice that of the configuration in FIG. 24.

[0119] In the various embodiments described above, four screw members are arranged in a cross shape on the screw arrangement surface, but the number and arrangement of the screw members on the screw arrangement surface are not limited to these. Figure 32 shows an example in which a surface-threaded assembly is composed of three screw members 10. The tip surfaces of the three screw members 10 form a triangular liquid flow gap 15.

[0120] In addition, in the configuration of FIG. 24, when the inner diameter of the liquid flow path 3 (throttling portion 609) is expanded, the total flow cross-sectional area becomes 3.8 mm 2 As long as the above conditions are met and the in-plane flow area ratio is ensured to be 40% or more, the number of screw members arranged on one screw arrangement surface, i.e., the number of screw members constituting the surface thread assembly, may be more than four, for example, six or eight. Figure 33 shows an example of a surface thread assembly composed of eight screw members.

[0121] Furthermore, when threaded members are arranged along the inner diameter (diameter) of the liquid flow path 3 (throttle section 609), a configuration in which the center gap is omitted can be achieved by using threaded members that traverse the inner diameter. FIG. 34 shows an example in which a surface thread assembly is configured using four threaded members without forming a center gap. FIG. 35 shows an example in which two sets of surface threaded assemblies from FIG. 34 are arranged, shifted in position in the direction of the central axis O and with an angular phase shift of 45°. In particular, in a high-flow nozzle in which the inner diameter of the throttle section 9 exceeds 10 mm, sufficient flow velocity near the central axis O can be ensured even if the center gap is omitted, and there is no obstacle to increasing the number of thread grooves near the central axis O where high flow velocity occurs.

[0122] (Experimental example) Below, the results of experiments conducted to confirm the various effects of water treated using the liquid treatment nozzle of the present invention will be described. Various test liquid treatment nozzles (hereinafter referred to as "test nozzles") were created with the shape shown in Figure 24. Figure 42 illustrates the dimensional relationship between the various parts of Figure 24. The cavitation core 1 was made of ABS resin, and the inner diameters of the inlet-side opening 604 and outlet-side opening 605 were φ20 mm, and the lengths in the flow direction of the inlet-side tapered section 606 and outlet-side tapered section 607 were 15 mm and 45 mm, respectively. In the cavitation treatment section, the length L of the throttling section 609 was set to various values ​​from 12 mm (up to 4 thread sets) to 17 mm (8 thread sets), and the inner diameter D of the throttling section 609 was set to various values ​​from φ4.2 (2 holes) to φ11.5 mm.

[0123] The screw components used were JIS:B0205 (1997)-specified No. 0 Class 1 pan head machine screws with a metric coarse pitch, made of stainless steel (SUS304). The nominal thread diameters of the stems were M1.0 (thread pitch: 0.25 mm, screw head outer diameter: 1.8 mm), M1.4 (thread pitch: 0.30 mm, screw head outer diameter: 2.0 mm), M1.6 (thread pitch: 0.35 mm, screw head outer diameter: 2.4 mm), and M2.0 (thread pitch: 0.40 mm, screw head outer diameter: 3.0 mm). The thread height mtd of each screw was approximately 50% of the thread pitch, and the inner diameter of the stem insertion portion 19f of the screw mounting hole 19 was set so that the aforementioned lap length ftd was 0.31 mtd. The number of thread placement surfaces (face thread sets) in the cavitation treatment unit ranged from 1 to 8, with various face spacings. For comparison, a liquid processing nozzle was also created in which two throttling sections 9 were formed in the partition section 8 formed in the cavitation processing section, and four screw members 10 were arranged in a cross shape for each throttling section 9, as shown in Figure 41.

[0124] The number and layout of the threaded members (surface thread sets) on each screw arrangement surface are three as shown in Figure 32, four as shown in Figures 4A and 4B, and eight as shown in Figure 33. The positional relationship (angular phase) of the surface thread sets on adjacent screw arrangement surfaces is either the same phase as shown in Figures 24, 26, and 27, or 45° or 60° as shown in Figures 28 to 30 (if there are three or more screw arrangement surfaces, they are alternately arranged with a 45° or 60° offset). In addition, the total flow cross-sectional area a of each screw arrangement surface is 5.1 to 56.8 mm 2 The in-plane flow area ratio was set to various values ​​ranging from 26.0% to 73.7%. Note that the test nozzles No. 13 and No. 15 in Table 3 were configured to include one screw arrangement surface with only two screw members arranged in the diameter direction (indicated as "1 / 2" in the table).

[0125] In addition, the number of 70% valley points inside the reference circle on each thread arrangement surface was counted on a projected image showing the layout of the threaded member within the throttle section, and the sum of the counts for each thread arrangement surface was divided by the total cross-sectional area of ​​the throttle hole to calculate the 70% valley point area density for each test nozzle. For each nozzle created, the values ​​for the throttle section inner diameter, number of internal threads, number of threads, thread arrangement, thread spacing, in-plane flow cross-sectional area of ​​each thread arrangement surface, in-plane flow area ratio of each thread arrangement surface, flow rate, total number of 70% valley points, 70% valley point area density, and 70% valley point flow density are summarized in Tables 1 to 4. Note that nozzles marked with an * are reference nozzles (nozzles within the scope of the present invention, but with some values ​​outside the preferred values). Each test nozzle in Tables 1 and 3 uses a threaded member with a nominal thread diameter of M1.4.

[0126] [Table 1]

[0127] [Table 2]

[0128] [Table 3]

[0129] [Table 4]

[0130] The following tests were carried out using the above test nozzle. (1) Water flow test The test equipment shown in Figure 43 was constructed and each test nozzle was installed to conduct a water flow test. Specifically, tap water with a temperature of 20°C and a dissolved oxygen concentration of 6 ppm was poured into a 50-liter storage tank. The piping system was constructed using PVC pipes with an inner diameter of 20 mm. One end of the suction pipe was connected to the suction side of the vane pump, and the other end was inserted into the storage tank. The pump discharge pipe branched into a test pipe equipped with the test nozzle and a relief pipe that did not pass through the test nozzle. Water passing through the relief pipe returned to the storage tank. A test nozzle was attached to the end of the test pipe, and a dynamic water pressure gauge and flow meter were inserted upstream of it. By operating the vane pump in this state, the dynamic water pressure and flow rate could be measured when the test nozzle was open and water was passing through. The treated water that passed through the test nozzle was collected in a recovery tank. A flow control valve is provided on the relief pipe, and by adjusting its opening, the dynamic water pressure and flow rate applied to the nozzle can be set to any desired value in a stepless manner.

[0131] In the water flow test, the flow rate was measured for all test nozzles when the dynamic water pressure was fixed at 0.077 MPa, and for several particularly selected test nozzles, the change in flow rate was measured when the dynamic water pressure was changed in various ways.In addition, a separate test was conducted to examine the relationship between the flow cross-sectional area and flow rate when the dynamic water pressure was fixed at 0.077 MPa, using test nozzles with only one screw arrangement surface, with the number and layout of screw members (face thread assembly) set to four as shown in Figure 4A, and with the total flow cross-sectional area a changed in various ways by changing the inner diameter of the restrictor portion 609 and the nominal thread diameter M of the screw member 10.

[0132] (2) Slimy stain cleaning power evaluation test Using ground natto as a model of slimy soil similar to biofilm, the detergency of tap water passed through each test nozzle was evaluated using apparatus 2200 shown in Figure 40. Sprinkler nozzle 2201, which is the main part of apparatus 2200, is a PVC pipe with an inner diameter of 20 mm, the tip of which is sealed with a cap, and multiple nozzle holes are drilled through the pipe wall at 5 mm intervals in the axial direction of the pipe. This sprinkler nozzle is supported horizontally, and test water is supplied to the base end, causing it to spray downward from each nozzle hole.

[0133] The above-mentioned sprinkler nozzle was installed in place of the test nozzle in the system shown in Figure 43. In addition, since the treated water that was subjected to cavitation treatment as it passed through the test nozzle in the water flow test (1) was collected in a collection tank, this was installed in place of the storage tank (however, the collected water was obtained by setting the dynamic water pressure to 0.077 MPa). Using Figure 43 as an example, the treated water in the collection tank was sucked up by the vane pump and sprayed from the sprinkler nozzle instead of the test nozzle. Directly below the sprinkler nozzle 2201, a straightening tile 2207 was installed in a vertical position. The sprinkler nozzle 2201 was tilted forward around its axis so that the water flow hit the top surface of the straightening tile 2207 at an angle toward the user. The water flow WF sprayed from each nozzle hole spread and united on the straightening tile 2207, forming a water film that flowed downward.

[0134] The sample tile 2206 coated with the dirt model NT was placed directly below the rectifying tile 2207, and the water film-like water flow WF from the rectifying tile flowed down evenly across its width. The sample tile 2206 was tilted approximately 3° by the spacer 2205, with its lower end protruding forward. The width of the water jetting area of ​​the water spray nozzle 2201 was approximately 30 cm. The rectifying tile 2207 and sample tile 2206 were made of ceramic with a smooth white glaze layer on one side, and had a height TH of 9 cm and a width TW of 18 cm. The width of the dirt model NT on the sample tile 2206 was set to 3–4 cm, and the total flow rate of the sprayed treated water was adjusted to 6 L / min, with the actual flow rate hitting the dirt model NT adjusted to 0.6–0.7 L / min. As a result, the removal of the dirt model NT was primarily due to the penetration of the slime layer that adhered natto particles to the tile, rather than the kinetic energy of the water jet collision.

[0135] The soiling model NT was made from crushed natto, dyed red and applied to sample tile 2206. The size of the bean particles contained in the crushed natto was 2–3 mm, and the total weight of the application was standardized to 1 g (40–50 particles) using a digital scale. After applying the soiling model NT, the sample tiles were dried for 90 minutes in an air-conditioned room at 20°C and 50% RH before being used for testing. During the test, video footage was taken of the natto particles falling and being removed from sample tile 2206 as the cleaning progressed, and the change in the ratio of the number of removed particles to the initial total number of particles on sample tile 2206 over time was recorded from the video. Specifically, the same test was repeated three times for both treated water and regular water, and the average water flow time required for a 50% removal rate was read.

[0136] The detergency of the treated water was evaluated based on the water flow time described above, but the following method was used to facilitate comparison between ordinary tap water that had not been subjected to cavitation treatment and water treated using different test nozzles. The treated water was collected in a collection tank and allowed to stand for 10 minutes before being subjected to testing. After 10 minutes of standing, the treated water was checked for the presence of fine bubbles using a laser diffraction particle sizer (Shimadzu Corporation: SALD2200) to determine whether fine bubbles could be measured. The measurement results for water treated using any of the test nozzles, along with ordinary tap water, were below the detection limit. (On the other hand, when treated water passed through a test nozzle satisfying the preferred requirements of the present invention (nozzles without * marks) was immediately subjected to measurement, fine bubbles with an average bubble diameter of approximately 100 to 200 nm were detected.) Cleaning performance was evaluated not by cross-sectionally comparing the absolute values ​​of water flow time between treated water from multiple test nozzles, but by comparing the water flow time ratio (removal rate: 50%) between treated water and normal water (blank water) that had not been subjected to cavitation treatment when using sample tiles prepared under the same conditions.The above test results are summarized in Tables 1 to 4.

[0137] The results obtained are explained below. Figure 36 is a graph showing the results of examining the relationship between the total cross-sectional area a and the flow rate ρ when test nozzles with only one screw arrangement surface and variously changed total cross-sectional area (area of ​​the liquid flow region) of the screw arrangement surface were prepared, in addition to the nozzles used in the tests listed in Tables 1 to 4, and the dynamic water pressure was fixed at 0.077 MPa, which is the normal water pressure range. As is clear from this graph, when the total cross-sectional area a of the screw arrangement surface is 5.0 mm 2 In the above region, as the area a increases, the flow rate ρ becomes a linear function of a: ρ=1.75a+2.93 (I) On the other hand, when the total cross-sectional area a is 5.0 mm 2 In the region where the flow rate ρ is less than 1 / 2, the flow rate ρ deviates downward from the above linear relationship and becomes a function that depends on the logarithm of the total flow cross-sectional area a as follows: ρ = 9.28 × ln(a) - 3.37 (II) This is because under normal water pressure conditions, the total flow cross-sectional area a is 5.0 mm 2When the total cross-sectional area a is less than 5.0mm, the pressure loss increases rapidly with each additional thread insertion in the nozzle, and it becomes impossible to obtain a flow rate commensurate with the cross-sectional area. 2 A specific condition for this corresponds to, for example, when the inner diameter of the throttle portion 9 is set to 4.2 mm and four M1.4 screw members are arranged according to the layout of FIG. 4A.

[0138] In addition, to further increase the 70% valley point area density, the total flow cross-sectional area a is set to 5.0 mm 2 To explain why it is important to ensure the above, a test nozzle with two screw arrangement surfaces and an increased number of surface thread sets was prepared and a separate test was conducted. Figure 37 is a graph showing the results. The horizontal axis shows the flow velocity distribution in the cross-sectional radial direction of the throttle hole that forms a circular screw arrangement surface. Since a screw member is arranged within the cross section, it is natural to think that the shape of the flow velocity distribution will be affected by this. However, considering the symmetry of the screw member arrangement, it is generally considered reasonable to assume a parabolic flow velocity distribution with a maximum value at the central axis O, just as in the case where no screw member is arranged within the cross section (solid line in the figure). From this state, if the inner diameter of the throttle section 9 is reduced to 3.5 mm, for example, the total flow cross-sectional area a will be 3.5 mm. 2 Even in this region, if we consider that the flow rate ρ changes according to the linear function shown in equation (I) with respect to the area a, then a = 3.5 mm 2 The flow rate estimated from the extrapolated value to is approximately 9.0 L / min. However, due to the increase in pressure loss, the flow rate in this region is actually governed by equation (II), which includes the logarithm of a, and is found to be around 8.3 L / min, 10% lower than the above extrapolated value of equation (I).

[0139] In this case, if the effect of pressure loss is small even in this region and equation (I) holds, the flow velocity distribution in the cross-sectional radial direction is a = 5.0 mm 2 However, in reality, the flow velocity distribution in the cross-sectional radial direction is the same as that in the case of a=5.0 mm, as shown by the dashed line in Figure 37. 2At the position where the cross-sectional radius is 70%, the flow velocity is approximately half of the maximum value ρM. Therefore, if the maximum flow velocity is reduced by 10% from the value extrapolated by equation (I), then a = 5.0 mm 2 According to calculations, the cross-sectional radius position where the flow rate is 1 / 2 of the maximum value ρM in this case is reduced from the 70% position to the 67% position. If another set of threaded connections with such characteristics is added in the direction of the central axis O, the cross-sectional radius position where 1 / 2 of ρM is obtained is further reduced to the 63% position.

[0140] When the inner diameter of the drawn portion 9 is 3.5 mm and the nominal thread diameter M of the threaded member is 1.4, the geometric calculation shows that the number of 70% thread roots is 8, while the number of 63% thread roots is reduced to half, 4. 2 Even if two sets of threads are arranged in the direction of the central axis O, doubling the number of threaded elements in the flow passage cross section, the pressure loss will increase and the number of thread grooves will not be able to increase by 70% compared to when there is only one set of threads. 2 In the case of a surface thread set as above, the pressure loss increase when two sets are arranged in the central axis direction is a = 3.5 mm 2 Therefore, an increase in the number of thread threads will theoretically contribute to an increase in the number of 70% thread valleys, i.e., an increase in the 70% valley point area density. The lower limit of the total flow cross-sectional area a is, for example, 3.8 mm 2 It is preferable to set the value at 5.0 mm, where the above formula (I) is satisfied. 2 It is recommended to set the above. As will be described in detail below based on experimental results, when a configuration is adopted in which the four cross-shaped threaded members that make up the surface thread assembly are arranged in phase on adjacent thread arrangement surfaces (i.e., the legs of the threaded members are arranged in a positional relationship in which they overlap each other while aligning their longitudinal directions), the increase in pressure loss associated with the addition of the surface thread assembly is almost eliminated, and the number of 70% thread roots can be dramatically increased. Furthermore, even when the surface thread assembly is arranged with the angular phase shifted on adjacent thread arrangement surfaces, the increase in pressure loss associated with the addition of the surface thread assembly can be suppressed by increasing the distance between the surface thread assembly, and the number of 70% thread roots can be similarly increased.

[0141] Figure 38 shows the results of water flow tests using test nozzles (numbers 1 to 5, hereafter referred to as 45° nozzles; in Table 1, only numbers 2 and 4 were used for the cleanability evaluation). The inner diameter of the constriction was 5.0 mm, and the thread assemblies were made up of four cross-shaped thread members (M1.4) with a thread spacing of 1.4 mm to 8.4 mm (1.0 mm to 6.0 mm, where M is the nominal thread diameter). These nozzles were arranged at an angular phase offset of 45° from each other, as shown in Figure 28. The dynamic water pressure was set to various values ​​from 0.046 MPa to 0.089 MPa, and the measured flow rate values ​​are plotted against the set dynamic water pressure. Also shown are results for a nozzle with only one thread member (number 101), a nozzle with only one thread member but with eight thread members (number 102), and a nozzle with a two-hole type constriction hole (number 103) as shown in Figure 41.

[0142] According to the above results, when the face spacing dp is 1.4 mm (1.0 m), which is equal to the nominal thread diameter, the increase in pressure loss is greater than that of nozzle No. 101, which has only one set of threads. However, the flow rate is greater than that of nozzle No. 102, which has eight threads arranged on the same surface. This clearly demonstrates the effect of distributing the threads along the central axis O to reduce pressure loss. Furthermore, nozzle No. 2, which has an increased face spacing dp of 1.5 m, exhibits a significant increase in flow rate, demonstrating a significant reduction in pressure loss. This tendency becomes even more pronounced as the face spacing dp is further increased (No. 3: dp = 3.0 m). When the face spacing dp reaches 4.5 m, the flow rate characteristics are nearly identical to those of nozzles No. 101 and No. 103, which do not have multiple threads along the central axis O. In other words, by adopting this type of face spacing, adding threads with a shifted angular phase hardly increases pressure loss.

[0143] Figure 39 shows the results of a water flow test using test nozzles (numbers 6 and 8) with a 5.0 mm inner diameter at the choke section, four cross-shaped threaded members (M1.4) with a face spacing dp of 2.1 mm (=1.5 M), and two to eight sets of these nozzles arranged in phase with one another, as shown in Figures 24, 26, and 27. The hydrodynamic pressure was set to various values ​​from 0.046 MPa to 0.089 MPa, and the measured flow rate values ​​are plotted against the set hydrodynamic pressure values. The results for the 45° nozzle (number 2) in Figure 38, which has the same thread spacing, are also shown. By arranging the threaded members in phase, we can see that even when the number of threaded members is increased to eight, there is almost no increase in pressure loss. It is also clear that the flow rate values ​​are significantly higher than those of the 45° nozzle (number 2) with the same face spacing.

[0144] The results of the slimy soil cleaning power evaluation tests conducted for each nozzle are described below with reference to Tables 1 to 4. Table 1 shows the results for the 45° nozzles (numbers 2 and 4) and the in-phase nozzle (number 6) used in the water flow test, along with the results for the reference nozzles (numbers 101 to 103). Number 200 also shows the results when ordinary tap water not subjected to cavitation treatment was used as blank water (ordinary water). As mentioned above, the evaluation was performed based on the ratio of the water flow time of treated water to that of blank water when the removal rate was 50% (removal rate: 50%). When this water flow time ratio value is 1, the cleaning power for slimy soils is equivalent to that of blank water, and when it is less than 1, it means that slimy soils can be removed in a shorter time than with blank water. The smaller the absolute value, the better the cleaning power for slimy soils.

[0145] First, the results for the reference nozzles will be explained. The water treated with nozzle number 101, which has only one set of threads, had a water flow time ratio less than 1, and its cleaning power was better than that of the blank water. The results for nozzle number 102, which has only one set of threads but has eight threads, and nozzle number 103, which has two orifices, also showed better cleaning power than the blank water.

[0146] Here, the nozzle number 102 has a 70% valley point area density that is about 1.8 times that of the nozzle number 101, and shows a particularly good cleaning effect. 2 The flow velocity at the thread root is considered sufficient to generate cavitation, but the in-plane flow area ratio is relatively low at 26%, and the flow rate is also low at 6.8 L / min. The soil cleaning performance evaluation test was also conducted using treated water diluted 2-fold (or 3-fold) with blank water. Even with the 2-fold dilution, nozzle 102 exhibited a favorable water flow time ratio of 0.5 or less. The table also shows the calculated 70% valley point flow density, obtained by dividing the 70% valley point number by the water flow rate at a dynamic hydraulic pressure of 0.077 MPa. It can be seen that the higher this value, the better the cleaning performance indicated by the water flow time ratio. This is thought to be due to the larger proportion of the total flow rate that passes through the thread root, where bubble nucleation due to cavitation becomes prominent. In order for the tendency for cleaning ability to increase as the 70% valley point flow density increases, it is necessary to ensure a sufficient flow velocity at the 70% valley point to generate cavitation. This does not mean that the smaller the total flow cross-sectional area and the smaller the total flow rate, the more pronounced the cavitation will be.

[0147] Next, the results for test nozzles Nos. 2, 4, and 6 according to the embodiment of the present invention show that the 70% valley point area density is larger than that of nozzles Nos. 101 and 103, and therefore the cleaning ability of treated water is clearly superior. On the other hand, in comparison of the 70% valley point flow rate density, it is slightly inferior to nozzle No. 102, and although the cleaning ability does not reach that of nozzle No. 102, it exhibits a similar ability, and in addition, compared to nozzle No. 102, the in-plane flow area ratio is increased, and therefore the flow rate shows very good results.

[0148] Table 2 compares the results for nozzles No. 7 and No. 8, which have an increased number of threads in the same phase arrangement, with the results for test nozzles No. 101 and No. 6. For nozzles No. 7 and No. 8, the increase in pressure drop with the increase in the number of threads is small, so the 70% valley point area density and 70% valley point flow density both increase significantly while maintaining a high flow rate. As a result, the cleaning performance indicated by the water flow time ratio is good even when the dilution rate is increased by two or three times.

[0149] Table 3 summarizes the results for test nozzles (numbers 9 to 15) using M1.4 threaded members with various variations in the inner diameter of the constriction, the number of threads in the thread set, and the number of thread sets. Numbers 109, 111, 112, and 113 represent reference nozzles with only one thread set, the same configuration as test nozzles 9, 11, 12, and 13. Nozzle 10 uses the thread set shown in Figure 32, which is composed of three threaded members. Nozzle 15 has a constriction inner diameter greater than 10 mm and eight thread sets, as shown in Figure 17. Nozzles 13 and 15 use four to eight thread sets, but the number of threads in one layer is reduced by half (for four thread sets, only two threads are diametrically opposed, and for eight thread sets, only four threads are thinned to a cross shape). In the test nozzles of the examples Nos. 9 to 15, the flow rate increased to 30 L / min or more due to the enlargement of the inner diameter of the constricted portion 609, but the 70% valley point area density was 2.0 pieces / mm 2 The above results were achieved, demonstrating significantly better cleaning performance than the reference nozzle.

[0150] Table 4 shows the results for test nozzles (numbers 21 to 24) in which the in-plane flow cross-sectional area of ​​each thread arrangement surface was set to approximately the same value, while the 70% valley point density was set to various values ​​by changing the nominal thread diameter of the threaded component used. All of them exhibited good cleaning performance, but nozzles 22 to 24, which used threaded components with large thread root depths of M1.4 to M2.0, achieved equivalent cleaning performance at a lower 70% valley point area density than nozzle 21, which used a threaded component with a small thread root depth of M1.0. [Explanation of symbols]

[0151] 1 Cavitation Core 1M core body 3 Liquid flow path 9A Core flow path (liquid flow path) 10. Screw member 10f Legs 10h head 10mt male thread 15 Liquid Flow Gap 19 Screw mounting holes 19f Leg insertion part 19ft female thread 19h Head compartment 50 Nozzle casing 50B casing body 50A Core holding part 56 Storage passage 54 First side opening 55 Second side opening 100~600 Liquid processing nozzle

Claims

1. A liquid treatment nozzle that is incorporated into a piping system for circulating a liquid, a nozzle casing having an accommodation passage portion that is open at both ends; a core body having a through-type liquid flow path formed therein, the liquid inlet opening at one end face and the liquid outlet opening at the other end face, the core body being disposed in the accommodation passage section in a positional relationship such that the liquid supplied toward the inlet opening formed in the nozzle casing can pass through the liquid flow path and flow out of the outlet opening of the nozzle casing through the liquid flow path, the core body having a screw mounting hole formed therein through from the outer peripheral surface to the inner peripheral surface of the liquid flow path, and a cavitation core having a screw member whose head and base end sides of the legs are held in the screw mounting hole of the core body and whose tip end sides of the legs protrude from the inner surface of the liquid flow path, the cavitation core causing dissolved gas in the liquid that comes into contact with the cavitation treatment section to precipitate to supersaturation, a side of the nozzle casing where one of the liquid inlet and the liquid outlet is located is defined as a first side in a flow direction of the liquid, and a side where the other is located is defined as a second side, and the nozzle casing comprises a casing main body constituting the first side and a core pressing portion constituting the second side, The casing body has a second end surface on which a core insertion port is opened, and the accommodating passage portion is formed. The core pressing portion holds the cavitation core accommodated in the accommodation passage portion by connecting the first side end of the core pressing portion with the second side end of the casing body, and prevents the cavitation core from falling out. A liquid treatment nozzle characterized in that a nozzle side threaded joint portion that threads into a first threaded joint of the piping system is provided on one of the first side end of the casing body and the second side end of the core pressing portion, and a cap nut that threads into a male threaded portion that forms a second threaded joint of the piping system is freely fitted and rotatable on the other.

2. A liquid treatment nozzle as described in claim 1, wherein the cap nut is rotatably fitted onto the second side end of the core pressing portion, and the outer surface of the casing body is formed with a tool engagement portion having at least one pair of parallel surfaces for engaging a fastening tool used when assembling the liquid treatment nozzle to the piping system.

3. The second side end of the casing body extends beyond the second side end face of the cavitation core inserted into the accommodating passage portion, and an assembly female screw portion is formed on the inner peripheral surface of the second side end, a male assembly thread portion that threadably engages with the female assembly thread portion of the casing body is formed on the outer peripheral surface of the first side end portion of the core pressing portion, and the core pressing portion holds the cavitation core in place by threadably fastening the male assembly thread portion to the male assembly thread portion, A liquid treatment nozzle as described in claim 1, wherein a tool engagement hole is formed axially through the second side end of the core pressing portion, which hole forms part of the liquid flow path and is for engaging an assembly tool used when screwing the assembly male thread portion of the core pressing portion into the assembly female thread portion of the casing body.

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