Liquid spray device

Abstract

To provide a device capable of spraying a liquid in which the bubble number density in the fine bubble region, especially the ultrafine bubble region, is remarkably increased while using a simple mechanism. [Solution] This liquid spray device is provided with: a container for storing a liquid; a flow path member for guiding the liquid in the container to a spray nozzle; a pump for suctioning the liquid through the flow path member and spraying the liquid from the spray nozzle; and a cavitation processing member that is disposed within the flow path of the flow path member so as to contact the liquid which flows through the flow path due to the pump and that forms a plurality of distributed cavitation points which locally increase the flow velocity of the liquid on the contact surface with the liquid. The liquid flow cross-sectional area of the flow path at the location of the cavitation processing member is set to be larger than the flow cross-sectional area of the spray port of the spray nozzle.

Description

liquid spray device

[0001] The present invention relates to a liquid spray device.

[0002] Patent Document 1 discloses an aerial spray microbubble nozzle for spraying microbubble (fine bubble) water into the air. Patent Document 2 discloses a spray product in which a liquid is filled in a container A together with compressed gas and a valve mechanism with a spray member is provided.

[0003] JP 2015-100720 A Japanese Patent No. 6746382 A JP 2004-358284 A

[0004] NanotechJapan Bulletin Vol. 8, No. 4, 2015 Special feature "Collabo Nanotechnology" <4th> Pages 1-6

[0005] The microbubble nozzle for aerial spraying described in Patent Document 1 requires a nozzle with a special inlet for introducing air. This nozzle also requires a special structure for mixing the introduced air with pressurized water, which is cumbersome. The same is true for the spray product described in Patent Document 2, which fills a liquid with compressed gas.

[0006] Furthermore, in fine bubble water obtained by this type of pressurized dissolution mechanism, bubble growth tends to progress as the pressure is released, making it difficult to increase the number density of fine bubbles that can be retained in the liquid, and there is a problem in that it is particularly difficult to ensure a number density of bubbles in the ultrafine bubble range.

[0007] An object of the present invention is to provide an apparatus that can spray a liquid with a significantly increased bubble density in the fine bubble region, particularly in the ultrafine bubble region, using a simple mechanism.

[0008] In order to solve the above problems, the liquid spray device of the present invention comprises a container for storing liquid, a flow path member that leads the liquid in the container to a spray nozzle, a pump that sucks the liquid through the flow path member and sprays it from the spray nozzle, and a cavitation treatment member that is arranged within the flow path of the flow path member so as to come into contact with the liquid flowing through the flow path by the pump, and has multiple cavitation points formed in a dispersed manner on the contact surface with the liquid that locally increase the flow rate of the liquid, and is characterized in that the liquid flow cross-sectional area of ​​the flow path at the position where the cavitation treatment member is arranged is set larger than the flow cross-sectional area of ​​the spray outlet of the spray nozzle.

[0009] According to the present invention, an apparatus can be realized that uses a simple mechanism to spray a liquid with a significantly increased bubble density in the fine bubble region, particularly in the ultrafine bubble region.

[0010] 1. A cross-sectional view showing an example of a liquid treatment device of the present invention. 1. A cross-sectional view showing an enlarged press-down head of the liquid treatment device of FIG. 1. 2. A cross-sectional view showing an enlarged periphery of an air cylinder of the liquid treatment device of FIG. 1. 3. A cross-sectional view explaining the operation of the liquid treatment device of FIG. 1. 4. An enlarged view of the cavitation nozzle of the liquid treatment device of FIG. 1. 5. A longitudinal cross-sectional view of FIG. 6. A bottom view showing a first example of an arrangement of a screw member in a flow hole. 6. A bottom view showing a second example of an arrangement of a screw member in a flow hole. 7. A schematic diagram explaining how bubble nuclei in droplets grow to become bubbles during spraying. 8. A diagram showing another example of a cavitation nozzle. 9. A cross-sectional view showing an embodiment in which a screw member is screwed directly into the wall of a suction tube. 10. A cross-sectional view showing an example configuration of a liquid treatment device using the suction tube of FIG. 11. 11. A histogram showing the calculation results of number density by bubble diameter class for Example 1 and Comparative Example 1. 12. A histogram showing the calculation results of volume density by bubble diameter class for Example 1 and Comparative Example 1. 13. A histogram showing the calculation results of number density by bubble diameter class for Example 2 and Comparative Example 1. 10 is a histogram showing the calculation results of the volume density by bubble diameter class in Example 2 and Comparative Example 1. FIG. 11 is a histogram showing the calculation results of the number density by bubble diameter class in Example 3 and Comparative Example 2. FIG. 12 is a histogram showing the calculation results of the number density by bubble diameter class in Example 3 and Comparative Example 2. FIG. 13 is a histogram showing the calculation results of the number density by bubble diameter class in Example 4 and Comparative Example 2. FIG. 14 is a histogram showing the calculation results of the volume density by bubble diameter class in Example 4 and Comparative Example 2. FIG. 15 is a histogram showing the calculation results of the number density by bubble diameter class in Example 106 and Comparative Example 2. FIG. 16 is a histogram showing the calculation results of the volume density by bubble diameter class in Example 106 and Comparative Example 2. FIG. 17 is a histogram showing the calculation results of the number density by bubble diameter class in Example 118 and Comparative Example 1. 10 is a histogram showing the calculation results of the volume density by bubble diameter class for Example 118 and Comparative Example 1.

[0011] An embodiment of the present invention will now be described with reference to the accompanying drawings. Figure 1 shows a cross-sectional view of a liquid sprayer 1 according to one embodiment of the present invention. The liquid sprayer 1 is configured as a sprayer and includes a container A filled with a liquid L, a cylinder member B, and an actuating member C. The container A has a neck portion 3 extending from a cylindrical body 2. The cylinder member B has a small-diameter liquid cylinder 5 extending from the lower portion of a large-diameter air cylinder 4 and hanging down into the container A. In the illustrated example, the upper end of the air cylinder 4 is fixed to an attachment cap D. The attachment cap D has a flange-shaped top wall 7 extending inward from the upper end of a peripheral wall 6 fitted onto the outer surface of the neck portion 3 of the container A, and a guide tube 9 extending from the inner periphery of the top wall 7. An engagement ridge with a hook-shaped cross section protruding outward from the upper outer periphery of the air cylinder 4 is fixed by being fitted into an engagement recess on the underside of the top wall 7. A small-diameter liquid cylinder 5 hangs down from the inner periphery of an inward flange-shaped bottom wall 10 at the lower end of the air cylinder 4, and a suction tube 11 hangs down from the lower end of the cylinder to the bottom of the container body. A cavitation nozzle 50, which will be described later, is detachably attached to the lower end of the suction tube 11.

[0012] The type of liquid L may be, but is not limited to, water, an aqueous solution (for example, lotion), an organic solvent such as alcohol, or a mixture thereof.

[0013] 2 and 3, the actuating member C has a stem 12 that rises from within the liquid cylinder 5, a push-down head 13 that is fitted onto the upper end of the stem 12, and an air cylinder 4 that incorporates a large-diameter cylindrical piston 14. The middle portion of the stem 12 is inserted through the center of the large-diameter cylindrical piston 14 that is fitted into the air cylinder 4. The push-down head 13 is biased upward and is movable up and down, and a spray nozzle 15 is installed horizontally within the upper portion of the push-down head.

[0014] The spray nozzle 15 comprises a first member 15a and a second member 15b arranged coaxially. The first member 15a is cylindrical and embedded in the push-down head 13. An air outlet passage a is formed in the first member 15a, axially communicating with the air cylinder 4. The second member 15b is fitted into a recess in the push-down head 13, covering the front end of the first member 15a and forming a small gap 28 (which forms part of the liquid outlet passage b). The front side of the second member 15b opens as the spray nozzle 16. A liquid outlet passage b is formed on the exterior of the spray nozzle 15, connecting the spray nozzle 16 to the interior of the stem 12. As shown in Figure 12, when the actuating member C is depressed, air is ejected from the spray nozzle 16 through the air outlet passage a, creating a negative pressure in the liquid outlet passage b. This negative pressure draws up the liquid in the container, mixes with the ejected air, and is sprayed.

[0015] 2 and 3, a small-diameter cylindrical piston 17 is fitted inside the liquid cylinder 5, and a push-down head 13 is fitted to the upper end of a stem 12 that protrudes from the outer periphery of the lower end of the small-diameter cylindrical piston 17. The push-down head 13 comprises a horizontal cylinder 19 that is open at its front end and that is horizontally installed inside the upper part of a casing 18 that is a closed-topped cylindrical casing with a top wall 18b extending from the upper end of a peripheral wall 18a. A spray nozzle 15 with a spray outlet at its tip is fitted inside the horizontal cylinder 19. The push-down head 13 also comprises a vertical inner cylinder 20 that hangs down with its upper end communicating with the horizontal cylinder 19 and whose lower end is fitted to the upper end of the inner periphery of the stem 12, and a vertical outer cylinder 21 that hangs down around the outer periphery of the vertical inner cylinder 20 and whose lower end hangs down with a gap from the upper end of the outer periphery of the stem 12.

[0016] A base tubular portion 14a extends through the center of the large-diameter cylindrical piston 14 fitted into the air cylinder 4. The upper part of the base tubular portion 14a is airtightly fitted to the inner surface of the lower part of the vertical outer cylinder 21 of the depression head 13 so as to be able to move up and down with a small stroke. The stem 12 is urged upward by a coil spring 22 provided in the small-diameter liquid cylinder 5, and this upward urging presses the lower surface of the movable valve element (described later) against the upper surface of the partition wall portion 14b of the large-diameter cylindrical piston 14, and the lower end surface of the base tubular portion 14a against the upper surface of a seat 23 attached to the outer surface of the middle part of the stem 12.

[0017] A partition wall 14b is provided between the base cylindrical portion 14a and the outer peripheral cylindrical portion 14c of the large-diameter cylindrical piston 14. The radially intermediate portion of the partition wall 14b is an upright cylindrical portion, and a plurality of ambient air intake valve holes 24 are formed in the partition wall portion that contacts the base cylindrical portion 14a. A synthetic resin cylindrical portion 25 is airtightly fitted to the lower outer surface of the base cylindrical portion 14a, and a flange-shaped elastic thin plate 26 is provided on the lower outer surface of the synthetic resin cylindrical portion 25 and protrudes upward and outward. The outer peripheral edge of the flange-shaped elastic thin plate 26 is pressed against the underside of the partition wall 14b outward of the ambient air intake valve holes 24, forming an ambient air intake valve 27.

[0018] Air ejection path a is configured to communicate with the inside of spray nozzle 15, passing from the lower end surface of base tube portion 14a between stem 12 and base tube portion 14a, between stem 12 and vertical outer tube 21, and between vertical inner tube 20 and vertical outer tube 21, and further through small gap 28 to communicate with spray nozzle 16. Liquid outlet path b runs from inside stem 12 through vertical inner tube 20, through a through hole 29 drilled in horizontal tube 19, and further through a gap 30 around spray nozzle 15 and small gap 28 to communicate with spray nozzle 16. An air discharge valve 31 is formed by the lower end surface of base tube portion 14a and the upper surface of catch 23, and a liquid stop valve 32 is provided in stem 12.

[0019] Furthermore, an engagement rib 33 is provided around the stem 12. A plurality of engagement upright plates are vertically mounted on the inner surface of the lower portion of the small-diameter fluid cylinder 5, and an upward engagement step is provided on the inner surface of the middle portion. Meanwhile, the upper portion of a rod 34 is inserted into the stem 12. A plurality of engagement protrusions are attached to the outer surface of the lower portion of the rod 34, which fit freely up and down between the engagement upright plates. The upper end of the rod 34 is hemispherical, with a larger diameter portion at the top, and its outer surface is watertightly engaged with the upper surface of the engagement rib 33, forming a leak-proof valve 35. A coil spring 22 is disposed between the lower portion of the small-diameter fluid cylinder 5 and the small-diameter cylindrical piston 17, allowing the rod 34 to be inserted loosely. The lower end of the spring 22 is placed on the engagement step of the engagement upright plate, and urges the operating member C upward via the small-diameter cylindrical piston 17, while this upward urging pulls up the rod 34 via the engagement protrusion 33 to a state in which the engagement protrusion is pressed against the lower end surface of the coil spring 22.

[0020] In this embodiment, the air cylinder 4 is provided with an air inlet hole h to prevent negative pressure from occurring inside the container A when the liquid inside the container decreases due to spraying, and a movable valve E is provided to open and close the air inlet hole h. When the operating member C moves to the lowest locked state shown in Figure 4, the movable valve E is pushed down by the operating member C, causing the air inlet hole h to be closed. On the other hand, when the operating member C moves to the highest raised state shown in Figure 1, the movable valve E is pushed up by the large-diameter cylindrical piston 14, causing the air inlet hole h to be opened, and the air inlet hole h is maintained in an open state when the operating member C moves up and down to spray liquid.

[0021] The movable valve element E has a cylindrical seal 42 on its outer periphery fitted to the inner surface of the air cylinder 4 above the large-diameter cylindrical piston 14, and a flange-like wall 43 extending inward from the cylindrical seal 42 to a position near the outer periphery of the vertical outer cylinder 21. The flange-like wall 43 is stepped and extends upward to the center, with a pressing protrusion 44 protruding from its underside. When the coil spring 22 (elastic member) is in the normal upward biasing state, i.e., in the fully raised state, the pressing protrusion 44 is pushed up by the large-diameter cylindrical piston 14, and its upper surface is locked in place with the upper surface abutting against the underside of the top wall 7 of the attachment cap D. At this time, the cylindrical seal 42 is located above the outside air inlet hole h.

[0022] A downward step 45 formed by a protruding rib is provided at a predetermined position on the outer surface of the vertical outer cylinder 21. When the operating member C is pushed down from the uppermost position in Fig. 1 to the lowermost locked position in Fig. 4, the downward step 45 comes into contact with the inner peripheral edge of the upper surface of the flange-like wall 43 of the movable valve body E, and the cylindrical seal portion 42 is pushed down to a position where it closes the outside air introduction hole h.

[0023] In the initial state of the spray container 1, the liquid cylinder 5 is empty, and by moving the actuating member C up and down several times from the state shown in Figure 1, the liquid L is sucked in through the cavitation nozzle 50 and the suction tube 11, filling the liquid cylinder 5. When the actuating member C is pressed down from this state, first the stem 12 descends together with the depression head 13 relative to the large-diameter cylindrical piston 14, opening the air discharge valve 31, and then the lower end of the vertical outer cylinder 21 of the depression head 13 comes into contact with the upper surface of the partition wall portion 14b of the large-diameter cylindrical piston 14, and the large-diameter cylindrical piston 14 also descends together with the stem 12, with the air discharge valve 31 remaining open.

[0024] At this time, since the outside air intake valve 27 is closed, the air in the air cylinder 4 is ejected from the spray nozzle 16 through the air ejection path a and the small gap 28. Because the outer periphery of the small gap 28 is under negative pressure, the liquid outlet path b communicating with the small gap is also under negative pressure, and the liquid L in the liquid cylinder 5 is sucked into the small gap 28 via the liquid outlet path b, and the liquid L sucked into the small gap mixes with the ejected air and is ejected from the spray nozzle 16 as a mist.

[0025] When the depression head 13 is released, the air ejection stops, eliminating the negative pressure in the small gap 28 and closing the liquid stop valve 32. Furthermore, the stem 12 rises before the large-diameter cylindrical piston 14, closing the air discharge valve 31. The large-diameter cylindrical piston 14 is then also pulled up to its upper end position by the seat 23, creating a negative pressure inside the air cylinder 4. This causes the outside air suction valve 27 to open, drawing outside air into the air cylinder. Meanwhile, the liquid L in the container A is sucked into the liquid cylinder 5 via the suction tube 11. At this time, the movable valve body E remains in the position shown in FIG. 1, so the outside air inlet hole h remains open. As the negative pressure increases due to the decrease in liquid inside the container, outside air is introduced into the container A through the outside air inlet hole h.

[0026] The amount of liquid L sucked at this time is determined by the speed at which air flows into the cylinder 4 as the large-diameter cylindrical piston 14, which has expelled air from the cylinder 4 by one stroke of the press head 13, returns from the lower end position in FIG. 4 to the upper end position in FIG. 1. Because the elastic displacement of the coil spring 22 corresponding to the depression stroke when the press head 13 is pressed down to the lower end position is approximately constant, the upward movement of the large-diameter cylindrical piston 14 is also considered to be approximately constant due to the elastic restoring force of the coil spring 22 corresponding to the elastic displacement. When the press head 13 is continuously pressed down naturally with a finger (e.g., the index finger or thumb of the dominant hand), the operating time required for the depression stroke of the press head 13 and the time required to return the finger in preparation for the next press are approximately equal. The elastic restoring force of the coil spring 22 is adjusted so that the press head 13 returns to the upper limit position within the time it takes to return the finger. To achieve stress-free continuous pressing operations, it is desirable that the time it takes for the press head 13 to return from the lower limit position to the upper limit position be approximately equal to the time required for one press stroke of the press head 13 during spraying (= the time required for one shot of spraying).

[0027] A device having a configuration in which the cavitation nozzle 50 is omitted from the liquid spraying device 1 of Fig. 1 is the same as that disclosed in Patent Document 3. However, the configuration of the liquid spraying device to which the present invention is applicable is not limited to this. For example, the liquid spraying device 1 of Fig. 1 is configured to mix the liquid in the container with the drawn-in air before spraying it from the spray nozzle 16, but a spraying device configured to spray only the liquid from the spray nozzle 16 without mixing it with air may also be used.

[0028] Returning to Figure 1, in the liquid spray device 1, the cavitation nozzle 50, suction tube 11, liquid cylinder 5, stem 12, and vertical inner cylinder 20 constitute a flow path member that guides the liquid L in the container A to the spray nozzle 15. In addition, the depression head 13, air cylinder 4, and large-diameter cylindrical piston 14 constitute a pump that sucks the liquid L through the flow path member and sprays it from the spray nozzle 15.

[0029] 5 and 6, the cavitation nozzle 50 is configured such that a screw member 54 (made of metal: stainless steel, titanium, or the like) is assembled to a resin nozzle body 51 so that a leg portion 54f is exposed inside a flow hole 53 formed through the nozzle body 51. In this embodiment, the screw member 54 is arranged so that the leg portion 54f is aligned in the diameter direction of the flow hole 53, which has a circular cross section.

[0030] The screw member 54 may be threaded into a female threaded hole formed in the nozzle body 51, or may be integrated with the nozzle body 51 by insert molding. Furthermore, as shown in Fig. 10 , a plurality of screw members 54 may be arranged in the flow direction within the flow hole 53 of the nozzle body 51. In Fig. 10 , two screw members 54 are arranged in a twisted positional relationship in which the axes of the legs 54 form a 90° angle. In order to suppress an increase in pressure loss within the flow path, the legs 54 of the plurality of screw members 54 are preferably arranged so that the distance between their inner edges in the flow direction is greater than the nominal diameter of the threads (preferably 1.3 times or more the nominal diameter).

[0031] When a liquid is passed through the flow hole 53, the flow velocity distribution tends to increase locally at the thread roots formed in the leg portions 54f. That is, in the threaded member 51, the thread roots function as cavitation points CP. The leg portions 54f are formed with multiple spiral threads. As shown in FIGS. 7 and 8, in the axial cross section of the flow hole 53, multiple thread roots appear arranged axially at thread pitch intervals along both radial sides of the leg portions 54f. The threaded member 5 constitutes a cavitation treatment member in which multiple cavitation points CP that locally increase the flow velocity of the liquid are dispersed on the contact surface with the liquid. Note that the cavitation treatment member in the present invention is not limited to a threaded member, and may be substituted, for example, with a rod member having dispersed unevenness that serves as cavitation points on its outer circumferential surface.

[0032] 4 includes a pump that sucks liquid L through a flow path member and sprays it from the spray nozzle 15, and a screw member 54 (cavitation treatment member) that is disposed within a flow hole 53 (flow path) of the flow path member so as to come into contact with the liquid L flowing through the flow hole 53 by the pump, and that has a plurality of dispersed cavitation points CP that locally increase the flow rate of the liquid on the contact surface with the liquid L. The liquid flow cross-sectional area of ​​the flow hole 53 at the position of the screw member 54 (the area of ​​the portion obtained by excluding the projected area of ​​the screw member 54 from the projected area of ​​the circular flow hole 53 when projected on the axial cross section shown in FIGS. 7 and 8 ) is set larger than the flow cross-sectional area of ​​the spray port 16 of the spray nozzle 15.

[0033] The inventors have found that the liquid sprayed from the nozzle 16 of the liquid spray device 1 configured in this manner has a significantly higher density of bubbles of 1 μm or less (so-called ultra-fine bubbles) than a liquid sprayed using a liquid spray device configured without the screw member 54 (cavitation treatment member). The inventors speculate that the mechanism behind this is as follows.

[0034] By operating the push-down head 13, the liquid L in the container A passes through the cavitation nozzle 50, then passes through the suction tube 11, the liquid cylinder 5, the stem 12, and the vertical inner cylinder 20, and is then introduced into the spray nozzle 15, where it is mixed with air and sprayed as a mist from the spray nozzle 16. Here, cavitation points CP (thread roots) are dispersed within the flow hole 53, and although the average value of the liquid flow velocity within the flow hole 53 is relatively small, the flow is constricted near the bottom of the V-shaped thread roots, and centrifugal force is also applied due to collisions with and detouring by the circular cross-section thread legs 54f, so the local flow velocity near the bottom of the roots becomes considerably high.

[0035] According to Bernoulli's theorem, the high flow rate region near the valley bottom becomes a negative pressure region, and based on the difference in the amount of dissolved air between normal pressure and negative pressure, the dissolved air that has not yet dissolved precipitates under reduced pressure, generating bubble nuclei (cavitation). The reduced pressure region where bubble nuclei precipitate is limited to the vicinity of the valley bottom, and the liquid flow passes through this region instantaneously, and then returns to normal pressure. Therefore, it is thought that most of the generated bubble nuclei stop growing in the nucleus state. The exact size of the bubble nuclei is unknown, but for example, Non-Patent Document 1 describes how, in an image of water treated with a swirling flow type ultrafine bubble (UFB) generator, which was flash frozen and observed with an ultra-high voltage electron microscope, fine spots with an average diameter of 10 nm or less were observed, for example, at a number density of 8.1 × 10 １７ It has been reported that approximately 1000 pieces / cc are observed. Although not discussed in the literature, the inventors believe that the spots appearing in the electron microscope photograph are quite likely to represent bubble nuclei, judging from their size and number density. The density of bubble nuclei of this size cannot be measured using general ultrafine bubble measuring devices (for example, laser diffraction particle sizers and nanotrunking measuring devices).

[0036] Thus, it can be considered that the liquid in the container is pre-treated by contact with the cavitation treatment member prior to being sprayed from the spray nozzle 16 to generate a considerable number of bubble nuclei (which do not grow into bubbles). As shown in Figure 9, when droplets LD containing bubble nuclei BN are mixed with air and sprayed from a small-diameter spray nozzle, the droplets BD are decompressed due to the high flow rate during spraying, and the dissolved air grows into measurable bubbles GB using the bubble nuclei BN as seeds. It is believed that the total volume of bubbles GB generated in the droplets LD increases as the density of bubble nuclei BN increases. Therefore, it is believed that spraying a liquid that has been pre-treated by contact with the cavitation treatment member and has an increased density of bubble nuclei can significantly increase the amount of bubbles generated compared to spraying a liquid that is not pre-treated.

[0037] An important point here is that if the density of bubble nuclei formed by pretreatment becomes excessive, the density of bubbles GB growing during spraying will become too high, causing adjacent bubbles to coalesce and escape from the droplet, thereby reducing the amount of ultra-fine bubbles that can be retained in the droplet. Therefore, in pretreatment using a cavitation treatment element, it is essential to adjust the flow rate so that the density of bubble nuclei formed does not become excessive. In the present invention, the liquid flow cross-sectional area of ​​the flow hole 53 (flow path) at the position of the screw member 54 (cavitation treatment element) is set larger than the flow cross-sectional area of ​​the spray outlet 16 of the spray nozzle 15. This adjusts the flow rate of the liquid contacting the cavitation treatment element to a level that does not result in excessive bubble nuclei formation density, suppressing bubble coalescence and floating up. As a result, the effect of generating a significantly greater amount of ultra-fine bubbles than when spraying a liquid without a cavitation treatment element is achieved.

[0038] Returning to Figure 4, the suction tube 11 has a first end connected to the suction side of the pump and a second end extending to a position facing the bottom surface inside the container A. In the configuration of Figure 1, a screw member 54 constituting a cavitation treatment member is attached to the suction tube 11 via the nozzle body 51 of the cavitation nozzle 50. The cavitation treatment member can also be incorporated into the cap D or the press-down head 13 in Figure 1, for example, but by attaching it to the suction tube 11 as described above, the structure can be greatly simplified.

[0039] If the cavitation treatment member is not installed airtightly on the suction tube 11, and the cavitation treatment member is exposed above the liquid surface in container A, gas above the liquid surface is sucked into the suction tube 11 through gaps where the airtightness is not ensured. When this happens, the sucked gas collides with the cavitation treatment member as bubbles, covering the cavitation points on the member and preventing bubble nucleation. In this case, it is desirable to attach the cavitation treatment member (threaded member 54) to the suction tube 11 in a position where it will be submerged below the liquid surface when the residual liquid level in container A is 50% of its full state. In this way, the cavitation treatment member (threaded member 54) remains submerged in the liquid L in container A until the residual liquid level decreases to 50% of its full state, effectively preventing the above-mentioned problems. In the configuration shown in Figure 4, the cavitation treatment member (threaded member 54) is attached to the second end of the suction tube 11 and is designed to remain submerged in the liquid until the liquid level further decreases. 6 , the upper end side of the flow hole 53 (flow passage) of the cavitation nozzle 50 is a tapered hole 55, and the second end of the suction tube 11 is press-fitted into the tapered hole 55 (flow hole) of the cavitation nozzle 50. This allows the cavitation nozzle 50 to be easily assembled to the suction tube 11. However, the assembly form of the cavitation nozzle 50 to the suction tube 11 is not limited to this. For example, a convex portion through which the flow hole 53 is formed may be formed on the cavitation nozzle 50, and this convex portion may be press-fitted into the suction tube 11.

[0040] 11, the screw member 54 may have its legs 54f directly screwed into the wall of the suction tube 11 from the outer circumferential surface side of the wall. In the liquid spray device 100 shown in FIG. 12, by using a suction tube 11 to which the screw member 54 is directly attached, it is not necessary to form a cavitation nozzle separately, and the structure can be further simplified.

[0041] When a screw member 54 is used as a cavitation treatment member, the number of thread grooves CP (cavitation points) of the screw member 54 present in the liquid flow cross section of the flow hole 53 (flow passage) at the position where the screw member 54 is disposed is determined by dividing the number of thread grooves by the liquid flow cross section area, and the value of the thread groove area density is 2 / mm ２ 20 pieces / mm or more ２ The thread groove area density is preferably 2 / mm or less. ２ If the cavitation treatment member is not provided, the amount of bubble nuclei generated will be insufficient, and the superiority in the amount of ultra-fine bubbles generated will be less than that when compared with when a liquid is sprayed without the cavitation treatment member. ２ If the pressure exceeds this value, the bubble nuclei will be formed at an excessive density, causing significant coalescence and floating of the bubbles, and the advantage in the amount of ultra-fine bubbles produced may become less pronounced.

[0042] As shown in FIG. 4, the liquid spray device 1 has a manual push pump pump, making it highly versatile for personal use and portable use. Such devices are filled with liquid L, such as lotion or alcohol, and the spray volume per push is adjusted to, for example, between 0.3 cc and 2 cc. Setting the spray volume per push to such a relatively small value adjusts the average flow velocity at the liquid flow cross section of the flow hole 53 (flow path) at the position of the screw member 54 to a relatively small value, thereby suppressing excessive bubble nuclei formation density and, ultimately, losses due to bubble coalescence and floating. An electric pump can also be used as the pump. Although the liquid spray device 1 is configured to spray a multiphase flow of liquid and air from the spray nozzle 16, it may also be configured to spray only the liquid. In this configuration, the liquid is depressurized when it is sprayed at high speed from the spray nozzle 16, and atomization is achieved by mixing the outside air immediately near the outlet of the spray nozzle 16 with the depressurized liquid flow, so the effects of the present invention can be achieved in the same way, except that the droplet size after spraying is slightly larger.

[0043] For example, when the spray volume per push is in the range of 0.3 cc to 2 cc, the spray time per push when an average adult operates the manual push pump with normal force is, for example, 0.2 seconds to 1.5 seconds. In this case, the average spray flow rate of the liquid in the liquid spray device 1 is, for example, about 30 cc / min to 200 cc / min. When the manual push pump is manually operated to achieve such an average spray flow rate, the average flow velocity in the liquid flow cross section of the flow path at the position of the screw member is preferably, for example, 0.05 m / sec to 1.2 m / sec. The value of the thread number flow density, obtained by dividing the number of thread roots CP of the screw member 54 present in the liquid flow cross section of the flow hole 53 (flow path) by the average spray flow rate, is preferably, for example, 0.08 bubbles / min to 0.80 bubbles / min. The effect of increasing the amount of ultra-fine bubbles generated compared to when spraying liquid without a cavitation treatment member is particularly significant within the above numerical range.

[0044] The results of various tests conducted to confirm the effects of the liquid spray device of the present invention are described below. (Test Example 1) As the liquid spray device for testing, a spray device having the shape shown in Figure 1 was prepared. For the main body of the spray device excluding the cavitation nozzle 50, two types (Spray 1 and Spray 2) were prepared, which differed in the inner diameter of the spray nozzle 16 and the amount of spray per push. Table 1 summarizes the characteristic values ​​of each spray device.

[0045]

[0046] Various cavitation nozzles 50 were prepared, as shown in Figures 5 and 6. The threaded members used were JIS No. 0, Class 1 pan head machine screws (coarse pitch), with two nominal diameters, M1.4 and M1.0, and a single thread count. The inner diameter, thread pitch and depth, number of thread roots, cross-sectional area, and thread root area density of the flow holes of the nozzle body used are shown in Table 2, along with the type of spray spraying device used (Table 1). The liquid flow cross-sectional area at the location of the threaded member 54 of the cavitation nozzle 50 was calculated by image processing, as shown in Figures 7 and 8, for example, by subtracting the projected area of ​​the leg portion 54f from the area of ​​the circle corresponding to the flow hole 53. Figure 7 shows a projection diagram for a case where an M1.4 threaded member was used, and Figure 8 shows a projection diagram for a case where an M1.0 threaded member was used (the inner diameter of the flow hole 53 is 2.5 mm). The number of thread roots CP can be counted on these projection diagrams.

[0047] Then, from the spray flow rate and liquid flow cross-sectional area shown in Table 1 for each spray spraying device, the average flow velocity of the liquid within the cross section at the position of the screw member 54 is calculated. In addition, the value of the thread root number flow density is calculated by dividing the number of thread roots CP by the spray flow rate.

[0048] A spray atomizer equipped with a cavitation nozzle 50 was filled with pure water (dissolved oxygen (DO: 6 ppm), and 15 cc of treated water sprayed into a beaker was collected by manually repeatedly operating the press-down head. The collected treated water was filled into a quartz batch cell, and the bubble number density in the ultra-fine bubble region was measured using a laser diffraction type high-sensitivity fine bubble measurement system (Shimadzu Corporation: SALD-7500 x 10) (Examples 1 to 4). For comparison, similar measurements were also made on treated water sprayed and collected from each spray atomizer without the cavitation nozzle 50 attached (Comparative Examples 1 and 2). The results are summarized in Table 2.

[0049]

[0050] Furthermore, the calculation results of the number density and volume density by bubble diameter class obtained by bubble measurement for each numbered example and comparative example are summarized in Tables 3 to 8.

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] As shown in Table 2, when using the liquid spraying device equipped with a cavitation nozzle, both when Spray 1 was used (Examples 1 and 2) and when Spray 2 was used (Examples 3 and 4), the measured bubble number density (in the ultra-fine bubble region of 1 μm or less) in the treated water was significantly higher, by several to 17 times or more, compared to when using a liquid spraying device without a cavitation nozzle (Comparative Example 1 and Comparative Example 2). It was also found that the treated water obtained using the liquid spraying devices of Comparative Examples 1 and 2, which were not equipped with a cavitation nozzle, also detected ultra-fine bubbles at a concentration of more than 2 billion bubbles / cc. This indicates that the pure water used originally contained a certain amount of bubble nuclei due to some cavitation history. However, it is presumed that the density of bubble nuclei in the treated water dramatically increased through pretreatment using the cavitation nozzle, and this growth during spraying is thought to have resulted in an overwhelming difference in bubble number density. The liquid spraying device of the Examples was able to increase the volumetric abundance of the ultra-fine bubble region by more than twice that of the Comparative Example. The results are explained in detail below.

[0058] Fig. 13 is a histogram showing the calculated number density by bubble diameter class for Example 1 compared with Comparative Example 1, and Fig. 14 is a histogram showing the calculated volume density for Example 1 compared with Comparative Example 1. The comparison of the number density histograms in Fig. 13 reveals that the distribution peak position for Example 1, which underwent pretreatment using a cavitation nozzle, is shifted toward the smaller diameter side compared to the case without a cavitation nozzle (Comparative Example 1). Furthermore, the comparison of the volume density histograms in Fig. 14 reveals that of the two peaks appearing in the ultra-fine bubble region (bubble diameter: 1 μm or less) and the fine bubble region with a bubble diameter of 5 μm or more, the former has a greater increase rate than the latter. In other words, these results demonstrate that pretreatment using a cavitation nozzle has the effect of preferentially increasing bubbles in the ultra-fine bubble region. The volume fraction of the ultra-fine bubble region in Comparative Example 1 is about 4.6 μL / L as shown in Table 7, whereas in Example 1 it is about 31.7 μL / L as shown in Table 3, which is about 7 times that of Comparative Example 1.

[0059] Fig. 15 is a histogram showing the calculated results of number density by bubble diameter class for Example 2 and Comparative Example 1, and Fig. 16 is a histogram showing the calculated results of volume density for Example 2 and Comparative Example 1, respectively. The distribution peak position in Example 2 is shifted toward smaller diameters than in Comparative Example 1, as in Example 1, but the absolute value of the ultra-fine bubble number density is lower than in Example 1. Furthermore, as is clear from the results in Fig. 16, the rate of increase in the peak of the fine bubble region relative to Comparative Example 1 is greater than the rate of increase in the peak of the ultra-fine bubble region. Because the thread root number flow density in Example 2 is higher than in Example 1, the bubble number density in the ultra-fine bubble region may be slightly excessive, and some of these bubbles may have coalesced, increasing the bubble number density in the fine bubble region. From Table 4, the volume fraction of the ultra-fine bubble region in Example 2 is approximately 13.2 µL / L, approximately 2.9 times that of Comparative Example 1.

[0060] FIG. 17 is a histogram showing the calculated number density by bubble diameter class for Example 3 and Comparative Example 2, and FIG. 18 is a histogram showing the calculated volume density for Example 3 and Comparative Example 2. The comparison of the number density histograms in FIG. 17 reveals that the distribution peak position in Example 3 is shifted toward smaller diameters than in Comparative Example 2. Furthermore, the comparison of the volume density histograms in FIG. 18 reveals that of the two peaks appearing in the ultra-fine bubble region and the fine bubble region, the former has a greater increase rate than the latter. This confirms that, as in Example 1, pretreatment using a cavitation nozzle has the effect of preferentially increasing bubbles in the ultra-fine bubble region. The volume fraction of the ultra-fine bubble region in Comparative Example 2 is approximately 1.9 μL / L, as shown in Table 8, whereas in Example 3 it is approximately 40.6 μL / L, as shown in Table 5, approximately 21 times that of Comparative Example 2.

[0061] Fig. 19 is a histogram showing the calculation results of number density by bubble diameter class for Example 4 and Comparative Example 2, and Fig. 20 is a histogram showing the calculation results of volume density for Example 4 and Comparative Example 2, respectively. The comparison of number density histograms in Fig. 19 shows that the distribution peak position in Example 4 is shifted to the smaller diameter side compared to Comparative Example 2. Furthermore, the comparison of volume density histograms in Fig. 20 shows that of the two peaks appearing in the ultra-fine bubble region and the fine bubble region, the increase rate in the former is greater than that in the latter, confirming that pretreatment using a cavitation nozzle has the effect of preferentially increasing bubbles in the ultra-fine bubble region.

[0062] Test Example 2: The same two types of spray atomizers as in Test Example 1 were prepared, and two types of cavitation nozzles with nominal diameters of M1.4 and M1.0 were used. The inner diameter, thread pitch and depth, number of thread grooves, cross-sectional flow area, and thread groove area density of the nozzle body were further varied, and the treated water was evaluated in the same manner as in Test Example 1. In Test Example 2, a cavitation nozzle with two screw members 54 (distance between the inner edges of the legs 54f: 2 mm) assembled in the configuration shown in Figure 10 was also tested. Two types of pure water were used: one with a dissolved oxygen content of 8 ppm and the other with a dissolved oxygen content of 6 ppm. The results are summarized in Table 9.

[0063]

[0064] These results show that the water treated by the liquid spraying device equipped with a cavitation nozzle has a higher bubble number density in the ultra-fine bubble region measured than the water treated by the liquid spraying device of Comparative Example 1 or Comparative Example 2 in Table 2, both of which are not equipped with a cavitation nozzle. In particular, when pure water with a dissolved oxygen content of 6 ppm is used, the bubble number density is found to be particularly high under conditions where the thread groove number flow rate density is 0.80 bubbles min / L or less.

[0065] Furthermore, for Examples 106 and 118, which have particularly high bubble number densities, the calculation results of number density and volume density by bubble diameter class obtained by bubble measurement are summarized in Tables 10 and 11.

[0066]

[0067]

[0068] FIG. 21 is a histogram showing the calculated number density by bubble diameter class for Example 106 compared with Comparative Example 2, and FIG. 22 is a histogram showing the calculated volume density for Example 106 compared with Comparative Example 2. The comparison of the number density histograms in FIG. 21 reveals that the distribution peak position for Example 106 is slightly shifted toward smaller diameters than for Comparative Example 2. Furthermore, the comparison of the volume density histograms in FIG. 22 reveals that of the two peaks appearing in the ultrafine bubble region and the fine bubble region, the former has a greater increase rate than the latter. This confirms the effectiveness of pretreatment using a cavitation nozzle in preferentially increasing bubbles in the ultrafine bubble region. As shown in Table 10, the volume fraction of the ultrafine bubble region in Example 106 is approximately 43.6 μL / L, approximately 22.9 times that of Comparative Example 2 (approximately 1.9 μL / L).

[0069] Figure 23 is a histogram showing the calculated number density by bubble diameter class for Example 118 compared with Comparative Example 1, and Figure 24 is a histogram showing the calculated volume density for Example 118 compared with Comparative Example 1. The comparison of the number density histograms in Figure 23 reveals that the distribution peak position in Example 4 is shifted toward smaller diameters than in Comparative Example 1. Furthermore, the comparison of the volume density histograms in Figure 24 reveals that of the two peaks appearing in the ultra-fine bubble region and the fine bubble region, the former again shows a greater increase than the latter, confirming that pretreatment using a cavitation nozzle has the effect of preferentially increasing bubbles in the ultra-fine bubble region. As shown in Table 11, the volume fraction of the ultra-fine bubble region in Example 118 is approximately 31.6 μL / L, approximately 6.9 times that of Comparative Example 1 (approximately 4.6 μL / L).

[0070] 1,100 Liquid spray device 5 Liquid cylinder 4 Air cylinder 11 Suction tube 12 Stem 13 Push-down head 14 Large diameter cylindrical piston 15 Spray nozzle 20 Vertical inner cylinder 50 Cavitation nozzle 54 Thread member (cavitation treatment member) A Container L Liquid CP Thread root portion (cavitation point)

Claims

1. A liquid spray device comprising a container for storing liquid, a flow path member for leading the liquid in the container to a spray nozzle, a pump for sucking the liquid through the flow path member and spraying it from the spray nozzle, and a cavitation treatment member disposed within the flow path of the flow path member so as to come into contact with the liquid flowing through the flow path by the pump, and having a plurality of distributed cavitation points formed on the contact surface with the liquid that locally increase the flow rate of the liquid, wherein the liquid flow cross-sectional area of ​​the flow path at the position where the cavitation treatment member is disposed is set larger than the flow cross-sectional area of ​​the spray nozzle's spray port.

2. The cavitation treatment member is a screw member whose thread root portion functions as the cavitation point, the thread pitch and thread root depth of the screw member are both 0.2 mm to 0.4 mm, and the liquid flow cross-sectional area of ​​the flow path at the position where the screw member is disposed is 2.5 mm ２ More than 15mm ２ 2. The liquid spray device according to claim 1, wherein the inner diameter of the spray nozzle is 0.2 mm or more and 1.0 mm or less.

3. The value of the thread groove area density obtained by dividing the number of thread grooves of the thread member present in the liquid flow cross section of the flow path at the position where the thread member is disposed by the liquid flow cross section area is 2 / mm ２ 20 pieces / mm or more ２ 3. The liquid spray device of claim 2, wherein:

4. A liquid spray device according to claim 2, wherein said pump is a manual push pump and the amount of liquid sprayed per push is between 0.3 cc and 2 cc.

5. A liquid spray device as described in claim 4, wherein when the manual push pump is manually operated so that the average spray flow rate of the liquid is 30 cc / min or more and 200 cc / min or less, the average flow velocity at the liquid flow cross section of the flow path at the position of the screw member is 0.05 m / sec or more and 1.2 m / sec or less, and the value of the thread groove number flow density obtained by dividing the number of thread grooves of the screw member present in the liquid flow cross section of the flow path by the value of the average spray flow rate is 0.08 pieces / min or more and 0.80 pieces / min or less.

6. A liquid spray device as described in any one of claims 1 to 5, wherein the flow path member has a suction tube having a first end connected to the suction side of the pump and a second end extending to a position facing the bottom surface within the container, and the cavitation treatment member is attached to the suction tube.

7. A liquid spray device as described in claim 6, wherein said cavitation treatment member is attached to said suction tube at a position where it is submerged below the liquid surface when the residual liquid level in said container is 50% of the full-filled state.

8. The liquid spray device according to claim 7, wherein said cavitation treatment member is attached to said second end of said suction tube.

9. A liquid spray device as described in claim 6, wherein the cavitation treatment member is a screw member whose thread root portion functions as the cavitation point, and the screw member is attached to a resin nozzle body formed separately from the suction tube so that the legs of the screw member are exposed within a flow hole formed through the nozzle body to form a cavitation nozzle, and the cavitation nozzle is detachably attached to the suction tube.

10. The liquid spray device according to claim 9, wherein said second end of said suction tube is press-fitted into said flow hole of said cavitation nozzle.

11. A liquid spray device as described in claim 6, wherein the cavitation treatment member is a screw member whose thread root portion functions as the cavitation point, and the leg portion of the screw member is screwed directly into the wall of the suction tube from the outer peripheral surface side of the wall.

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