Liquid ejecting apparatus

Abstract

The invention provides a liquid ejecting apparatus capable of ejecting a liquid containing nanobubbles with a simple structure. The liquid ejecting apparatus includes: one or more ejection ports that eject a liquid; a discharge device that discharges a liquid; a first flow path in which the liquid discharged from the discharge device flows toward the one or more discharge ports; and a microbubble generator disposed at a midway position of the first flow path, in which a small-diameter section having a smaller inner diameter than the inner diameter of a portion on the upstream side of the small-diameter section is provided in a tubular section provided to the microbubble generator. The microbubble generator generates microbubbles in the liquid by cavitation generated when the liquid flowing in the tubular part passes through the small-diameter part from the upstream side of the small-diameter part, and the cross-sectional area of the small-diameter part is equal to or greater than the total value of the opening areas of the one or more ejection ports.

Description

Technical Field

[0001] The present invention relates to a liquid ejecting device, and in particular to a liquid ejecting device capable of ejecting liquid containing nano bubbles. Background Art

[0002] Liquid ejection devices that eject liquid from an ejection port are used in a variety of fields. The ejected liquid is used for a predetermined purpose, and in order to efficiently achieve the purpose, a useful function or effect is sometimes given to the liquid. As an example, a situation in which microbubbles such as nanobubbles are mixed into a liquid can be cited (for example, see Patent Document 1).

[0003] The device described in Patent Document 1 comprises a gas injection unit for injecting gas into liquid, a pressurizing unit for pressurizing the liquid injected with gas to generate a pressurized gas-liquid mixed liquid, and a decompression unit for decompressing the gas-liquid mixed liquid to atmospheric pressure while conveying the gas-liquid mixed liquid. Furthermore, nano-sized bubbles are generated in the liquid by conveying the gas-liquid mixed liquid to the decompression unit.

[0004] According to the device described in Patent Document 1 constructed as above, a liquid containing nanobubbles can be sprayed. Moreover, for example, by applying the liquid containing nanobubbles to plants, the plants can grow well. Specifically, by generating nanobubbles in a liquid such as pesticides and spraying the liquid containing nanobubbles onto plants, plant diseases and insect pests can be effectively suppressed (see Patent Document 2).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2011-152513

[0008] Patent Document 2: Japanese Patent Application Publication No. 2015-097509 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] The device for ejecting the liquid containing nanobubbles is expected to have a relatively simple structure in consideration of the ease of installation and maintenance of the device. On the other hand, in the existing device, such as the device described in Patent Document 1, a mechanism for pressurizing the gas and mixing it into the liquid is required, and accordingly, a larger installation space is ensured for the device, and the number of devices constituting the device increases.

[0011] Furthermore, when improving an existing liquid ejection device to a device capable of ejecting a liquid containing nanobubbles, it is preferable to be able to perform the improvement with a simpler structure.

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the following problems. Specifically, an object of the present invention is to provide a liquid ejection device capable of ejecting a liquid containing nanobubbles with a simpler structure.

[0013] Another object of the present invention is to improve the existing liquid ejection device into a device capable of ejecting liquid containing nanobubbles using a simpler structure.

[0014] Solutions for solving problems

[0015] In order to achieve the above-mentioned purpose, the liquid ejection device of the present invention is characterized in that the liquid ejection device comprises: one or more ejection ports, which eject liquid; a discharge device, which discharges liquid; a first flow path, in which the liquid discharged from the discharge device flows toward the one or more ejection ports; and a microbubble generator, which is arranged at a midway position in the first flow path, and a small diameter portion is provided in the tubular portion possessed by the microbubble generator, and the inner diameter of the small diameter portion is smaller than the inner diameter of the portion on the upstream side of the small diameter portion. The microbubble generator generates microbubbles in the liquid through cavitation generated when the liquid flowing in the tubular portion passes through the small diameter portion from the upstream side of the small diameter portion, and the cross-sectional area of ​​the small diameter portion is greater than the total value of the opening areas of the one or more ejection ports.

[0016] According to the liquid ejection device constructed as described above, the liquid containing microbubbles generated by the microbubble generator passes through the ejection port, whereby the microbubbles are changed into nanobubbles. As a result, the liquid containing nanobubbles can be ejected from the ejection port using a relatively simple structure. In addition, by installing the above-mentioned microbubble generator on an existing liquid ejection device, the existing liquid ejection device can be improved into a device capable of ejecting liquid containing nanobubbles through simple improvements.

[0017] In addition, the liquid ejection device of the present invention may also have a reservoir for storing liquid. In this case, the ejection device may also suck and eject the liquid in the reservoir. In addition, preferably, the liquid ejection device of the present invention has a second flow path connected to the first flow path at a position downstream of the microbubble generator in the first flow path, and the end of the downstream side of the second flow path is connected to the reservoir.

[0018] According to the above structure, the liquid containing microbubbles is circulated through the reservoir, the discharge device and the microbubble generator. As a result, the number of microbubbles contained in the liquid flowing in the first flow path can be fully increased. In addition, when a solid substance such as fertilizer or medicine is dissolved in a liquid, the solid substance is easily dissolved in the liquid by circulating the liquid, and the solid substance can be well dispersed in the liquid.

[0019] In addition, the small diameter portion may also have the first small diameter portion and the second small diameter portion located at a position closer to the downstream side than the first small diameter portion. In addition, it may also be that an expanded diameter portion, a same diameter portion and a turbulence generating portion are provided between the first small diameter portion and the second small diameter portion inside the tubular portion. The expanded diameter portion may also be located at the downstream side of the first small diameter portion, and the inner diameter is expanded toward the downstream side. The same diameter portion may also be adjacent to the expanded diameter portion at the downstream side of the expanded diameter portion, and extend toward the downstream side in a state in which the inner diameter becomes the same length as the inner diameter at the end of the downstream side of the expanded diameter portion. The turbulence generating portion may also be arranged between the same diameter portion and the second small diameter portion, and is adjacent to the same diameter portion and the second small diameter portion respectively, and extends toward the downstream side in a state in which the inner diameter becomes the same length as the same diameter portion.

[0020] According to the above configuration, microbubbles can be efficiently generated in the microbubble generator, and the generated microbubbles can be miniaturized.

[0021] Furthermore, in the axial direction of the tubular portion, a step surface intersecting the axial direction may be provided between the inner wall surface of the turbulent flow generating portion and the inner wall surface of the second small diameter portion.

[0022] According to the above configuration, by generating turbulence in the flow of the liquid in the turbulence generating section, the microbubbles in the liquid can be further miniaturized.

[0023] In addition, a cylindrical convex portion may be provided in the turbulence generating portion, and the cylindrical convex portion may protrude toward the upstream side along the axial direction from the portion of the step surface surrounding the end of the upstream side of the second small diameter portion. In addition, a recess may be provided between the inner wall surface of the turbulence generating portion and the outer peripheral surface of the cylindrical convex portion.

[0024] According to the above configuration, turbulence is easily generated in the flow of the liquid in the turbulence generating section. As a result, microbubbles in the liquid can be further efficiently miniaturized in the turbulence generating section.

[0025] Furthermore, it is preferable that the discharge pressure when the discharge device discharges the liquid is set so that the pressure of the liquid when passing through the upstream end of the microbubble generator in the first flow path is 0.15 MPa or more.

[0026] According to the above configuration, the liquid can be made to flow in the tubular portion at a pressure required to generate microbubbles by passing the liquid through the inside of the tubular portion of the microbubble generator.

[0027] Alternatively, the microbubble generator may be composed of a nozzle, and the liquid containing microbubbles may flow out from the tip of the nozzle.

[0028] According to the above configuration, by arranging the nozzle, which is the microbubble generator, in the first flow path, the liquid containing nanobubbles can be ejected from the ejection port with a simple configuration. In addition, it becomes easy to install the microbubble generator in the existing liquid ejection device.

[0029] Furthermore, part of the first flow path may be constituted by a hose, and part of the hose may be connected to an end of the tubular portion of the microbubble generator.

[0030] According to the above-mentioned structure, it becomes easier to install the microbubble generator in the existing liquid ejecting device.

[0031] Effects of the Invention

[0032] According to the present invention, a liquid ejection device capable of ejecting liquid containing nanobubbles with a simpler structure is realized.

[0033] In addition, according to the present invention, it is possible to more easily improve an existing liquid ejecting device into a device capable of ejecting liquid containing nanobubbles. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of a vehicle with a liquid ejection device.

[0035] Figure 2 This is a conceptual diagram of a liquid ejection device according to one embodiment of the present invention.

[0036] Figure 3 This is an external view of the nozzle that makes up the microbubble generator.

[0037] Figure 4 It is a cross-sectional view of the nozzle constituting the microbubble generator.

[0038] Figure 5 This is an enlarged view of the turbulence generating section in the microbubble generator.

[0039] Figure 6 It is a diagram showing a jet outlet and a small diameter portion of a microbubble generator.

[0040] Figure 7 It is a cross-sectional view of an ejector constituting a microbubble generator according to a modified example. DETAILED DESCRIPTION

[0041] The liquid ejection device of the present invention will be described with reference to a preferred embodiment (hereinafter referred to as the present embodiment) shown in the drawings.

[0042] In addition, the following embodiments are only specific embodiments given to explain the present invention in an easy-to-understand manner, and do not limit the present invention. That is, the present invention can be changed and improved without departing from its main purpose. In addition, the present invention certainly includes its equivalents.

[0043] The material, size, shape, etc. of each device and each member constituting the liquid ejection device of the present invention can be arbitrarily set according to the purpose of the present invention and the technical level at the time of implementation of the present invention.

[0044] In addition, in this specification, "device" includes a situation where the components of the device can be handled as a unit in a state where the components of the device are stored in a housing. In addition, there may be a situation where the components of the device are separated from each other and each device exists in an independent state, but they cooperate to achieve a specific purpose and are aggregated as a "device". In addition, "device" is not limited to the above concept.

[0045] In addition, in this specification, the numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0046] <<Overview of Liquid Dispensing Device>>

[0047] Reference Figure 1 The following is an overview of the liquid ejection device (hereinafter referred to as the liquid ejection device 10) of the present embodiment. The liquid ejection device 10 is a device for ejecting a liquid containing nanobubbles. In the present embodiment, nanobubbles are generated in a liquid medicine and the liquid medicine containing nanobubbles is ejected. The liquid medicine containing nanobubbles is used, for example, in agriculture or plant cultivation (including gardening or home gardening).

[0048] Nanobubbles are ultrafine bubbles, which are tiny bubbles with a diameter of less than 1 μm and can remain contained in a liquid for a long time (about several months). In addition, nanobubbles are different from microbubbles whose bubble diameter is 1 μm to 100 μm.

[0049] The liquid medicine is an example of a liquid, which is an aqueous solution produced by dissolving a solid fertilizer or medicine in water or diluting a liquid fertilizer or medicine with water. The water is an example of a liquid, for example, ordinary water used in agriculture or plant cultivation (such as tap water, well water or river water). However, it is not limited to this, and the water may also be distilled water, pure water or ultrapure water, turbid water mixed with minerals or organic matter, etc. In addition, the solute dissolved in the water is not limited to solid substances, for example, it may also be other liquids other than water (such as liquid medicines or fertilizers, etc.).

[0050] It is well known that when a solid or liquid fertilizer is contained in water to generate a liquid medicine, if nanobubbles are contained in the liquid medicine, the growth of plants is promoted compared with a normal liquid medicine. In addition, it is well known that when a solid or liquid medicine (pesticide) is contained in water to generate a liquid medicine, the spreading effect can be improved by containing nanobubbles in the liquid medicine, and plant diseases and insect pests can be effectively prevented.

[0051] In this embodiment, if Figure 1 As shown, the liquid ejection device 10 has two or more ejection heads 11, and ejects the nanobubble-containing liquid medicine from the ejection outlet 12 provided in each ejection head 11. More specifically, the ejection outlet 12 of each ejection head 11 is small (small diameter), and the nanobubble-containing liquid medicine is ejected from the ejection outlet 12 in a mist state, that is, sprayed.

[0052] In this embodiment, the liquid ejection device 10 is as follows Figure 1 The vehicle 100 with a liquid spraying device is a so-called high-speed sprayer, which travels in a field where plants are cultivated while spraying a liquid medicine containing nanobubbles. At this time, the liquid medicine containing nanobubbles is sprayed in a mist state as described above, and the sprayed liquid medicine containing nanobubbles is diffused to the surroundings by wind sent from a blower 110 provided on the vehicle 100 with a liquid spraying device.

[0053] In addition, the vehicle (mobile body) equipped with the liquid ejecting device 10 is not limited to a high-speed sprayer, and may be, for example, a so-called boom sprayer.

[0054] In addition, the driving device of the liquid ejection device 10, specifically the driving motor of the pump 14 described later, is operated by transmitting the driving force from the engine of the vehicle 100 with the liquid ejection device. The liquid ejection device 10 is operated by each device in the device to eject (spray) the nanobubble-containing liquid from the ejection ports 12 of the plurality of ejection heads 11.

[0055] <<Configuration example of the liquid ejection device of the present invention>>

[0056] Next, refer to Figure 2 and Figure 3 The following describes a structural example of the liquid ejection device 10. In addition, in the following description, "upstream side" and "downstream side" are concepts used to indicate a position specified in the direction of the liquid flow (strictly speaking, a position when viewed from a reference position or device). Specifically, in the direction of the liquid flow, the side toward which the liquid is directed (in other words, the side closer to the ejection port 12) is the "downstream side", and the opposite side is the "upstream side".

[0057] like Figure 2As shown, the liquid ejection device 10 includes an ejection head 11, a liquid tank 13, a pump 14, and a microbubble generator 30. These devices are connected by a flow path 15, and the liquid medicine flows in the flow path 15. The structure of the liquid ejection device 10 is the same as that of a device mounted on an existing high-speed sprayer, except that it includes the microbubble generator 30. In other words, by introducing (adding) the microbubble generator 30 of this embodiment into the existing high-speed sprayer, the liquid ejection device 10 of this embodiment can be constructed.

[0058] The ejection head 11 is arranged at the most downstream side in the liquid ejection device 10, and has an ejection port 12 of the liquid, for example, having the same structure as the ejection nozzle of a known high-speed sprayer. In the present embodiment, the plurality of ejection heads 11 are arranged regularly or irregularly, for example, in a state of an arc-shaped row, so that the liquid (medical solution) is ejected radially.

[0059] The liquid medicine flowing in the flow path 15 enters the discharge head 11 and then passes through the discharge port 12 and is discharged to the outside of the discharge head 11, that is, into the atmosphere. In addition, as described above, since the diameter of the discharge port 12 is small, the liquid medicine is sprayed from the discharge port 12 in a mist form. The opening shape of the discharge port 12 is, for example, a circle, but is not limited thereto, and may also be a polygon such as a quadrilateral or a triangle, an ellipse, or an irregular shape. In addition, the number of discharge heads 11 provided in the liquid discharge device 10 is not particularly limited, and is preferably set to an appropriate number according to the area of ​​the region to which the liquid medicine sprayed from the discharge head 11 is applied.

[0060] The liquid tank 13 is a storage device for storing liquid medicine inside, and is composed of, for example, a sealed or semi-sealed container. The liquid tank 13 is provided with a water supply port 13a, and new water is added to the tank from the supply port 13a. In addition, the liquid tank 13 is provided with a liquid medicine discharge port 13b, and the liquid medicine discharged to the outside of the tank through the discharge port 13b is sucked in by the pump 14. Figure 2 As shown in FIG. 1 , a return port 13c of the chemical solution is provided in the liquid tank 13. The chemical solution flowing through the second flow path 18 described later flows into the tank through the return port 13c and is recovered.

[0061] In addition, solid substances such as fertilizers or drugs may be put into the liquid tank 13 from the supply port 13a and dissolved in water in the tank. That is, water, i.e., drug solution, in which solid substances are dissolved may be generated inside the liquid tank 13. In this case, a stirring device or the like may be provided inside the tank for the purpose of efficiently dissolving the solid substances in the liquid tank 13.

[0062] The pump 14 is a dispensing device that sucks the liquid medicine in the liquid tank 13 through the discharge port 13b and discharges the sucked liquid medicine. The pump 14 is composed of, for example, a plunger pump. However, the style and model of the pump 14 are not particularly limited, and it can be a positive displacement pump or a non-positive displacement pump such as a centrifugal type.

[0063] The pump 14 pressurizes the inhaled liquid medicine and discharges the pressurized liquid medicine from the discharge port 14a. Gas, specifically air, is mixed into the liquid medicine discharged from the pump 14, and an amount of air (dissolved air) corresponding to the discharge pressure at that location is dissolved in the liquid medicine just after passing through the discharge port 14a. In addition, in the present embodiment, considering the pressure loss in the flow path 15, the discharge pressure of the pump 14 is set so that the inflow pressure into the microbubble generator 30 is greater than 0.15 MPa. In other words, the performance (capacity) of the pump 14 is selected so that when the liquid medicine is discharged at a predetermined flow rate, the above-mentioned inflow pressure is greater than 0.15 MPa. The inflow pressure into the microbubble generator 30 refers to the pressure of the liquid (liquid medicine) when passing through the upstream end of the microbubble generator 30 in the first flow path 17 described later.

[0064] In addition, the upper limit of the above-mentioned inflow pressure is not particularly limited, but the higher the inflow pressure, the greater the number of microbubbles generated in the microbubble generator 30. Therefore, the above-mentioned inflow pressure is preferably set as high as possible. On the other hand, considering the pressure resistance and durability of the components constituting the flow path 15 and the equipment provided in the flow path 15, it is better to set the inflow pressure within the range not exceeding the above-mentioned performance, for example, it is better to set it in the range of 0.15MPa to 5.0MPa. If the inflow pressure is within this range, the cavitation effect can be further improved in the microbubble generator 30, and the dissolved air in the medicinal solution is easy to precipitate as microbubbles.

[0065] In addition, if Figure 2 As shown, the pump 14 of this embodiment includes a second discharge port 14b, an on-off valve V is installed on the downstream side immediately adjacent to the second discharge port 14b, and a hose H is connected to the end on the downstream side of the on-off valve V. Thus, when the on-off valve V is in an open state, the pump 14 is activated, so that the liquid medicine discharged from the pump 14 can be sent out through the hose H, and the liquid medicine discharged from the top end of the hose can be used.

[0066] The flow path 15 is a flow path for the flow of the drug solution, and is composed of piping, hoses, and devices such as the microbubble generator 30 that constitute a part of the flow path. The flow path 15 connects two devices arranged in the direction of the flow of the drug solution. In other words, one end of the flow path 15 between the two devices is connected to the device on the upstream side, and the other end of the flow path 15 is connected to the device on the downstream side. Here, "connection" includes the case of connection using a joint or welding, etc., and also includes the case of connection in a state of interposing a valve, etc.

[0067] In addition, if necessary, an on-off valve, a flow regulating valve, a pressure gauge, a flow meter and other measuring instruments, a filter, and an observation window for monitoring the flow state may be provided in the flow path 15. Figure 2 Specifically shown in.

[0068] In addition, if Figure 2 As shown, a part of the flow path 15 may also be constituted by a flexible hose H. In this case, the end of the hose H may be connected to a joint portion of at least one of two devices arranged along the direction of the flow of the liquid medicine. In addition, the end of the hose H may be fixed relative to the joint portion using an annular or cylindrical hose fixing fitting arranged at a position relative to the outer periphery of the end of the hose H. Furthermore, the end of the hose may be more firmly fixed to the joint portion by riveting the hose fixing fitting to the hose side. The hose H may be any one of a rubber hose, a resin hose, a metal flexible hose, a braided hose, or other hoses that can be used in agriculture or gardening.

[0069] In this embodiment, if Figure 2 As shown in FIG. 1 , the flow path 15 includes an inhalation flow path 16 connecting the liquid tank 13 and the pump 14, and a first flow path 17 extending from the discharge port 14a of the pump 14. The liquid medicine discharged from the liquid tank 13 flows toward the pump 14 in the inhalation flow path 16. The first flow path 17 is provided with a microbubble generator 30 at a midway position thereof, and extends to the discharge port 12 of the discharge head 11. Figure 2 As shown, a part of the first flow path 17 may be formed by a flexible hose H.

[0070] In addition, if Figure 2 As shown in FIG. 1 , the flow path 15 has a second flow path 18 for returning the liquid medicine discharged from the pump 14. The second flow path 18 is connected to the first flow path 17 at a position on the downstream side of the microbubble generator 30 in the first flow path 17. In other words, the second flow path 18 is a flow path branched from the first flow path 17 at a branching point located on the downstream side of the microbubble generator 30. One end of the second flow path 18, more specifically, the end on the side opposite to the side connected to the first flow path 17, is connected to the return port 13c of the liquid tank 13. A part of the liquid medicine (strictly speaking, the liquid medicine containing microbubbles) discharged from the pump 14 and passing through the microbubble generator 30 flows to the second flow path 18. Then, the liquid medicine flowing in the second flow path 18 is returned to the liquid tank 13. That is, in the liquid ejection device 10 of the present embodiment, a circulation type flow path is formed in which the liquid medicine containing microbubbles circulates through the liquid tank 13, the pump 14, and the microbubble generator 30.

[0071] As described above, the microbubble generator 30 is arranged at a midway position of the first flow path 17, and the medicinal solution flowing in the first flow path 17 passes through the interior of the microbubble generator 30. That is, the internal space of the microbubble generator 30 (specifically, the internal space of the tubular portion 31) constitutes a part of the first flow path 17. Moreover, the microbubble generator 30 generates microbubbles in the medicinal solution passing therethrough. Regarding the principle of generating microbubbles in the present embodiment, cavitation is forcibly generated in the microbubble generator 30, so that the pressure of the medicinal solution drops and negative pressure is generated. As a result, the dissolved air in the medicinal solution precipitates as microbubbles. As a result, the medicinal solution containing microbubbles flows out from the end (top) on the downstream side of the microbubble generator 30.

[0072] The liquid medicine flowing out of the microbubble generator 30, i.e., the liquid medicine containing microbubbles, flows in the first flow path 17, and soon reaches the ejection port 12 of the ejection head 11, and is ejected through the ejection port 12. At this time, the microbubbles mixed into the liquid medicine are further miniaturized, and most of them are changed into nanobubbles. As a result, the liquid medicine containing nanobubbles is ejected from the ejection port 12 (strictly speaking, it is sprayed).

[0073] In addition, the microbubble generator 30 of this embodiment is composed of Figure 3 The nozzle is configured as shown. The nozzle can be easily mounted on a flow path provided in a conventional high-speed sprayer, and more specifically, can be easily mounted on a first flow path 17 extending from a discharge port 14 a of a pump 14 to a discharge port 12 of a discharge head 11 .

[0074] To explain in more detail, Figure 3 As shown in the figure, threads 32 (external threads in detail) are formed at both ends of the tubular portion 31 of the nozzle. Threads (internal threads in detail) provided on a hose connector (not shown) are fitted into the threads 32, and the hose connector is connected to the end of the nozzle by fitting the threads together. In addition, by fitting the hose H constituting a part of the first flow path 17 into the stepped connector portion provided at the end of the hose connector, the nozzle as the microbubble generator 30 can be arranged at a midway position of the first flow path 17.

[0075] As described above, when a part of the first flow path 17 is formed by a hose H, a part of the hose H can be connected to the end of the tubular portion 31 of the microbubble generator 30 via the above-mentioned hose joint. Thus, the microbubble generator 30 can be retrofitted to an existing device (high-speed sprayer). That is, an existing high-speed sprayer can be improved to a device capable of spraying a drug solution containing nanobubbles using a relatively simple structure.

[0076] In addition, there is no particular limitation on the means and method for mounting the nozzle on the first flow path 17. For example, the existing pipe may be cut and the end of the nozzle may be joined to the cut pipe by welding. Alternatively, when a portion of the existing pipe is fixed by bolts using a flange, the portion of the pipe may be removed, the nozzle having a flange at the end may be arranged in the vacant space, and the nozzle may be fixed by bolts using the flange.

[0077] <<Structure of Microbubble Generator>>

[0078] Reference Figures 3 to 5 The structure of the microbubble generator 30 of this embodiment will be described.

[0079] The microbubble generator 30 is a nozzle-type device, such as Figure 3 As shown, a tubular portion 31 is provided. Figure 4 As shown in the figure, the tubular portion 31 has a small diameter portion 33 having an inner diameter smaller than the inner diameter of the upstream portion. That is, the inner diameter of the small diameter portion 33 is smaller than the inner diameter of the upstream portion of the small diameter portion 33 (strictly speaking, the portion adjacent to the small diameter portion 33 on the upstream side of the small diameter portion 33). In addition, the small diameter portion 33 has a first small diameter portion 38 and a second small diameter portion 42 located on the downstream side of the first small diameter portion 38.

[0080] like Figure 4 As shown in FIG. 1 , the tubular portion 31 has an inlet 34 as an opening end on the upstream side and an outlet 35 as an opening end on the downstream side. Figure 4 As shown, inside the tubular portion 31, the large diameter portion 36, the reduced diameter portion 37, the first small diameter portion 38, the expanded diameter portion 39, the uniform diameter portion 40, the turbulence generating portion 41, the second small diameter portion 42, and the ejection portion 43 are coaxially arranged from the inlet 34 toward the outlet 35. That is, inside the tubular portion 31, the expanded diameter portion 39, the uniform diameter portion 40, and the turbulence generating portion 41 are provided between the first small diameter portion 38 and the second small diameter portion 42.

[0081] The reduced diameter portion 37, the first small diameter portion 38, and the second small diameter portion 42 constitute a load generating portion 44. In the load generating portion 44, the flow rate of the liquid increases and negative pressure is generated in the liquid, resulting in cavitation. As a result, dissolved air in the liquid is precipitated as microbubbles. In addition, in the turbulence generating portion 41, as shown in FIG. Figure 5 As shown, by generating turbulence in the flow of the chemical liquid and increasing the pressure of the chemical liquid, the microbubbles generated on the upstream side of the turbulence generating unit 41 are miniaturized, and even finer microbubbles are generated.

[0082] In the present embodiment, from the viewpoint of ease of manufacture, the tubular portion 31 is preferably formed by connecting two cylindrical members (hereinafter referred to as the first member 51 and the second member 52) which are separated from each other. Figure 3 As shown in the figure, the first member 51 has a flange portion 53 at the outer peripheral edge of the downstream end, and the second member 52 has a flange portion 54 at the outer peripheral edge of the upstream end. Then, the first member 51 and the second member 52 can be connected by joining the flange portions 53 and 54 to each other and fixing them with bolts or the like. However, the tubular portion 31 is not limited to a structure that can be divided into the first member 51 and the second member 52, and can also be composed of a single component.

[0083] The end of the first member 51 opposite to the flange portion 53 serves as the inlet 34. Figure 4 As shown, the large diameter portion 36, the reduced diameter portion 37, the first small diameter portion 38, the expanded diameter portion 39 and the uniform diameter portion 40 are arranged in order from the upstream side inside the first member 51. The end of the second member 52 on the side opposite to the flange portion 54 becomes the outflow port 35, as shown in FIG. Figure 4 As shown, inside the second member 52, the turbulent flow generating portion 41, the second small diameter portion 42, and the ejection portion 43 are arranged in this order from the upstream side.

[0084] The large diameter portion 36 is a space located at the most upstream side inside the tubular portion 31, and extends toward the downstream side with its inner diameter being the same length from the upstream end to the downstream end of the large diameter portion 36. The inner diameter of the large diameter portion 36 is not particularly limited, and is preferably, for example, about 5 mm to 15 mm.

[0085] The reduced diameter portion 37 is a tapered space located on the downstream side of the large diameter portion 36 and adjacent to the large diameter portion 36 and having an inner diameter that gradually shortens toward the downstream side. The inner diameter of each part of the reduced diameter portion 37, in other words, the degree of reduction of the reduced diameter portion 37 is not particularly limited, and the inner diameter at the downstream end of the reduced diameter portion 37 can be reduced to about 1 / 3 of the inner diameter of the large diameter portion 36.

[0086] The first small diameter portion 38 is a space having an inner diameter smaller than that of the large diameter portion 36 located on the upstream side of the first small diameter portion 38. The first small diameter portion 38 is located on the downstream side of the reduced diameter portion 37 and is adjacent to the reduced diameter portion 37, and extends toward the downstream side in a state where its inner diameter is the same length as the inner diameter at the downstream end of the reduced diameter portion 37. The inner diameter of the first small diameter portion 38 is not particularly limited as long as it satisfies the formula 1 described later, and is preferably set to about 1 / 3 of the inner diameter of the large diameter portion 36, for example.

[0087] The expanded diameter portion 39 is a tapered space located on the downstream side of the first small diameter portion 38 and adjacent to the first small diameter portion 38 and having an inner diameter that gradually expands toward the downstream side. The inner diameter of each portion of the expanded diameter portion 39, in other words, the degree of expansion of the expanded diameter portion 39 is not particularly limited, and for example, the inner diameter at the downstream end of the expanded diameter portion 39 may be expanded to be approximately the same length as the inner diameter of the large diameter portion 36.

[0088] The uniform diameter portion 40 is a space adjacent to the expanded diameter portion 39 on the downstream side of the expanded diameter portion 39 and extending toward the downstream side in a state where the inner diameter becomes the same length as the inner diameter at the downstream end of the expanded diameter portion 39. The inner diameter of the uniform diameter portion 40 is not particularly limited, and may be, for example, substantially the same length as the inner diameter of the large diameter portion 36.

[0089] The turbulence generating portion 41 is a space having the same diameter as the same diameter portion 40, that is, it extends toward the downstream side with the inner diameter being the same length as the same diameter portion 40. The turbulence generating portion 41 is adjacent to the same diameter portion 40 on the downstream side of the same diameter portion 40. In other words, the turbulence generating portion 41 is arranged between the same diameter portion 40 and the second small diameter portion 42, and is adjacent to the same diameter portion 40 and the second small diameter portion 42, respectively.

[0090] The second small diameter portion 42 is a space whose inner diameter is smaller than the inner diameter of the same diameter portion 40 and the turbulence generating portion 41 located on the upstream side of the second small diameter portion 42. The second small diameter portion 42 is located on the downstream side of the turbulence generating portion 41 and is adjacent to the turbulence generating portion 41, and extends toward the downstream side in a state where its inner diameter becomes a certain length. The inner diameter of the second small diameter portion 42 is not particularly limited as long as it satisfies the formula 1 described later, and it is preferably, for example, set to about 1 / 3 of the inner diameter of the large diameter portion 36. In addition, the inner diameter of the second small diameter portion 42 and the inner diameter of the first small diameter portion 38 can also be the same length. In this case, the inner diameter of the small diameter portion 33 is equivalent to the inner diameter of each of the first small diameter portion 38 and the second small diameter portion 42. Alternatively, it can be that the inner diameter of one of the first small diameter portion 38 and the second small diameter portion 42 is smaller than the inner diameter of the other. In this case, the inner diameter of the small diameter portion 33 corresponds to the smaller inner diameter of the first small diameter portion 38 and the inner diameter of the second small diameter portion 42 .

[0091] The ejection portion 43 is a tapered space located at the most downstream side inside the tubular portion 31, located at the downstream side of the second small diameter portion 42 and adjacent to the second small diameter portion 42, and the inner diameter gradually increases toward the downstream side. The inner diameter of each part of the ejection portion 43, in other words, the degree of expansion of the ejection portion 43 is not particularly limited, and for example, the inner diameter at the downstream end of the ejection portion 43 may be expanded to be about 3 to 4 times the length of the second small diameter portion 42.

[0092] The following reference Figure 5 The structure of the turbulence generating portion 41 described above will be described in detail. The inner diameter of the turbulence generating portion 41 is much larger than the inner diameter of the second small diameter portion 42. That is, the inner diameter of the tubular portion 31 changes discontinuously at the boundary position between the turbulence generating portion 41 and the second small diameter portion 42. In other words, in the axial direction of the tubular portion 31, a step surface 45 intersecting (in detail, substantially orthogonal to) the above-mentioned axial direction is provided between the inner wall surface of the turbulence generating portion 41 and the inner wall surface of the second small diameter portion 42.

[0093] In addition, a cylindrical convex portion 46 is provided in the turbulent flow generating portion 41. Figure 5 As shown, the cylindrical protrusion 46 protrudes toward the upstream side along the above-mentioned axial direction from the portion of the step surface 45 that surrounds the upstream end of the second small diameter portion 42. The cylindrical space surrounded by the cylindrical protrusion 46 becomes a connecting portion 47 that communicates with the second small diameter portion 42. The length of the cylindrical protrusion 46 in the above-mentioned axial direction, that is, the protrusion amount, is not particularly limited, and can be, for example, about 3 to 5 mm.

[0094] In addition, in the turbulence generating section 41, an annular recess 48 is provided between the inner wall surface of the turbulence generating section 41 and the outer peripheral surface of the cylindrical protrusion 46. The drug solution flowing toward the downstream side in the turbulence generating section 41 enters the recess 48, and the drug solution entering the recess 48 collides with the step surface 45 and rebounds toward the upstream side. Figure 5 As shown, turbulent flow is generated near the cylindrical convex portion 46. In addition, the drug solution flowing in a turbulent state near the cylindrical convex portion 46 flows into the communication portion 47 located inside the cylindrical convex portion 46.

[0095] When the drug solution flows in the tubular portion 31 of the microbubble generator 30 configured as above, microbubbles are generated in the drug solution, and the drug solution containing microbubbles flows out from the outflow port 35 of the tubular portion 31. Specifically, the drug solution entering the tubular portion 31 from the inflow port 34 flows from the upstream side to the downstream side along the axial direction in the large diameter portion 36. Then, the drug solution flows in the reduced diameter portion 37 and the first small diameter portion 38, that is, in the load generating portion 44. At this time, the flow rate of the drug solution increases, so the pressure of the drug solution decreases, thereby generating negative pressure and cavitation, thereby causing the dissolved air in the drug solution to precipitate as microbubbles.

[0096] The liquid medicine flows further downstream and flows in the expanded diameter portion 39 and the uniform diameter portion 40. At this time, the liquid medicine flows (liquid flow) along the inner wall surfaces of the expanded diameter portion 39 and the uniform diameter portion 40. The liquid medicine soon enters the turbulent flow generating portion 41 and the concave portion 48, collides with the step surface 45, and rebounds to the upstream side (refer to Figure 5 ). As a result, turbulence is generated near the cylindrical protrusion 46, and the medicinal liquid is pressurized, resulting in that the microbubbles in the medicinal liquid are miniaturized. Then, the medicinal liquid in a turbulent state flows into the connecting portion 47 on the inner side of the cylindrical protrusion 46, and further flows to the downstream side, and flows in the second small-diameter portion 42 constituting the load generating portion 44. At this time, the flow rate of the medicinal liquid increases again, so the pressure of the medicinal liquid decreases, thereby generating a negative pressure in the liquid flow and causing cavitation. As a result, the dissolved air in the medicinal liquid flowing in the second small-diameter portion 42 precipitates as microbubbles, resulting in that the medicinal liquid contains sufficient microbubbles. Then, the medicinal liquid containing microbubbles flows in the ejection portion 43, and flows out (strictly speaking, ejects) from the top of the nozzle, i.e., the outflow port 35, which is the microbubble generator 30.

[0097] According to the above structure, when the medicinal liquid passes through the small diameter portion 33 from the upstream side of the small diameter portion 33 (specifically, the first small diameter portion 38 and the second small diameter portion 42) in the microbubble generator 30, the flow rate of the medicinal liquid increases, thereby generating negative pressure in the liquid flow and causing cavitation. Through this cavitation, the dissolved air in the medicinal liquid precipitates as microbubbles, and microbubbles are generated in the medicinal liquid. In addition, by generating turbulence in the turbulence generating portion 41, the microbubbles can be miniaturized. As a result, with a simple structure, microbubbles can be efficiently generated and miniaturized in the medicinal liquid when the medicinal liquid passes through the tubular portion 31 of the microbubble generator 30.

[0098] <<Regarding the size relationship between the ejection port and the small diameter portion in the microbubble generator>>

[0099] The liquid ejection device 10 of the present embodiment has one or more ejection ports 12 and a microbubble generator 30 composed of a tubular portion 31 provided with a small diameter portion 33. To explain in more detail, the liquid ejection device 10 of the present embodiment has a plurality of ejection ports 12, and a first small diameter portion 38 and a second small diameter portion 42 as the small diameter portion 33 are provided inside the tubular portion 31. Moreover, in the present embodiment, the cross-sectional area of ​​the small diameter portion 33 is equal to or greater than the total value of the opening areas of the plurality of ejection ports 12.

[0100] To explain more specifically, Figure 6 As shown, the number of the ejection ports 12 of the liquid ejection device 10 is N (N is a natural number greater than 2), the opening area of ​​the ejection port 12 is Sa, and the cross-sectional area of ​​the small diameter portion 33 is Sb. In this case, in this embodiment, the following formula 1 is satisfied.

[0101] Sb≥N×Sa (Formula 1)

[0102] The opening area of ​​the jet port 12 is the area of ​​the range surrounded by the outer edge of the jet port 12. In addition, in the present embodiment, the opening areas of the plurality of jet ports 12 are equal. The cross-sectional area of ​​the small diameter portion 33 is the area of ​​the cross section of the small diameter portion 33 that is orthogonal to the axial direction of the tubular portion 31, in other words, the area of ​​the portion surrounded by the edge (inner edge) of the small diameter portion 33 in the cross section. In addition, when the inner diameters of the first small diameter portion 38 and the second small diameter portion 42 are the same, the cross-sectional area of ​​the first small diameter portion 38 and the second small diameter portion 42 are equivalent to Sb. When the inner diameters of the first small diameter portion 38 and the second small diameter portion 42 are different, the cross-sectional area of ​​the small diameter portion 33 with the smaller inner diameter is equivalent to Sb. That is, in the structure in which the cross-sectional area of ​​the small diameter portion 33 changes in the tubular portion 31 of the microbubble generator 30, the minimum value of the cross-sectional area of ​​the small diameter portion 33 is sufficient to be greater than the total value of the opening areas of the plurality of jet ports 12.

[0103] Furthermore, when the above-mentioned formula 1 is satisfied, the microbubbles are changed into nanobubbles when the liquid medicine containing microbubbles generated by the microbubble generator 30 passes through the ejection port 12. That is, in the liquid ejection device 10 of the present embodiment, the plurality of ejection ports 12 and the small diameter portion 33 are configured in a manner satisfying the above-mentioned formula 1, so that the microbubbles generated by the microbubble generator 30 are miniaturized into the size of nanobubbles, and as a result, the liquid medicine containing nanobubbles is ejected (sprayed) from each ejection port 12.

[0104] <<About the effectiveness of this embodiment>>

[0105] In this embodiment, a medical solution containing nanobubbles can be ejected using a relatively simple structure. Specifically, in this embodiment, cavitation and turbulence are generated in the microbubble generator 30, thereby generating microbubbles in the medical solution passing through the microbubble generator 30. At this time, since the dissolved air in the medical solution is used to generate microbubbles, it is not necessary to separately inject pressurized gas into the medical solution in the microbubble generator 30, and it is not necessary to have equipment for pressurized gas injection, etc.

[0106] In addition, in the present embodiment, the ejection port 12 and the small diameter portion 33 in the microbubble generator 30 satisfy the above-mentioned formula 1. Thus, when the drug solution containing microbubbles passes through the ejection port 12, the microbubbles are miniaturized to become nanobubbles, and as a result, the drug solution containing nanobubbles is ejected from the ejection port 12. As described above, in the present embodiment, nanobubbles can be generated in the drug solution by making the cross-sectional area of ​​the small diameter portion 33 of the microbubble generator 30 equal to or greater than the total value of the opening area of ​​the ejection port 12. If such a feature is effectively utilized, for example, by installing the above-mentioned microbubble generator 30 in an existing high-speed sprayer, the drug solution containing nanobubbles can be ejected using a relatively simple structure.

[0107] In addition, in this embodiment, if Figure 2 As shown, the flow path 15 branches at the downstream side of the microbubble generator 30, and a part of the liquid medicine containing microbubbles flows from the first flow path 17 to the second flow path 18 and is returned to the liquid tank 13. That is, in this embodiment, the liquid medicine containing microbubbles circulates through the liquid tank 13, the pump 14 and the microbubble generator 30. As a result, the number of microbubbles contained in the liquid medicine flowing in the first flow path 17 can be fully increased. In addition, a part of the liquid medicine containing microbubbles is returned to the liquid tank 13, so that the path (i.e., the flow path 15) through which the liquid medicine flows becomes longer, so that solid substances such as fertilizers or drugs are easily dissolved in the water. In addition, the solid substances are easily dissolved in the water, so that the solid substances are well dissolved, and as a result, it is possible to suppress the formation of bubbles on the liquid surface in the liquid tank 13 by the solid substances remaining in the liquid tank.

[0108] <<Other implementation methods>>

[0109] The liquid ejecting device and the mobile body equipped with the liquid ejecting device of the present invention have been described above by taking one specific embodiment as an example, but the above embodiment is only an example, and other examples are also conceivable.

[0110] In the above-mentioned embodiment, the case where the liquid ejection device 10 has a plurality of ejection ports 12 is described as an example, but the liquid ejection device may have only one ejection port. In this case, the opening area of ​​the one ejection port 12 is equivalent to the total value of the opening areas of more than one ejection port, and the cross-sectional area of ​​the small diameter portion 33 provided in the tubular portion 31 of the microbubble generator 30 is larger than the opening area of ​​the one ejection port 12.

[0111] In the above-mentioned embodiment, as an example of the microbubble generator 30, Figure 3 to Figure 5 The nozzle of the structure shown, but not limited to this, can also be used Figure 7 The ejector shown serves as a microbubble generator 60 .

[0112] The inside of the ejector constituting the microbubble generator 60 does not have an expanded diameter portion 39, a uniform diameter portion 40, a turbulence generating portion 41, and a second small diameter portion 42, but has a gas injection portion 49 connected to the large diameter portion 36. Except for these points, the above-mentioned ejector has a structure substantially the same as the nozzle constituting the above-mentioned microbubble generator 30. The liquid medicine passes through the inside of such an ejector, thereby generating negative pressure in the flow of the liquid medicine, generating cavitation, and thereby generating microbubbles in the liquid medicine. However, if the structure of the above-mentioned nozzle-type microbubble generator 30 is used, microbubbles can be generated in the liquid medicine more efficiently, and the microbubbles can be miniaturized.

[0113] In the above-described embodiment, a case where a part of the first flow path 17 is formed of the hose H is described as an example. However, the entire first flow path 17 may be formed of a pipe or the hose H.

[0114] In addition, in the above-mentioned embodiment, a circulation type flow path 15 is constructed to return a part of the drug solution, i.e., the drug solution containing microbubbles, that has passed through the microbubble generator 30 to the liquid tank 13. However, this is not limited to this, and the drug solution flow path 15 may be a non-circulation type flow path, and the drug solution (i.e., the drug solution containing microbubbles) that has passed through the microbubble generator 30 is not returned to the liquid tank 13, but the entire amount thereof is ejected from the ejection port 12.

[0115] In addition, in the above-mentioned embodiment, the liquid ejection device (i.e., a high-speed sprayer or a boom sprayer, etc.) mounted on a vehicle is described, but it is not limited thereto. The liquid ejection device of the present invention can be a portable device that a user can carry with him or a fixed device. In addition, the portable device can be a shoulder-mounted device or a backpack-mounted device.

[0116] In addition, in the above-mentioned embodiment, each driving device in the liquid ejecting device is operated by the driving force transmitted from the engine of the vehicle 100 with the liquid ejecting device. However, it is not limited to this. The driving device of the liquid ejecting device 10 can also be operated by the power from the rechargeable battery (Battery) mounted on the above-mentioned vehicle or the power supplied from the commercial power supply or the power supply such as the solar panel. In addition, the driving device of the liquid ejecting device 10 can also be a manual device.

[0117] In addition, as described in the above-mentioned embodiment, the liquid ejection device of the present invention can also be formed by installing the microbubble generator 30 in an existing device (such as a high-speed sprayer or a boom sprayer). Alternatively, the liquid ejection device of the present invention can also be a newly manufactured device in which its various structural devices are assembled from scratch.

[0118] In addition, in the above-mentioned embodiment, as an example of liquid, a liquid medicine, i.e., water in which fertilizers or drugs are dissolved, is cited, but it is not limited to this. The liquid ejection device of the present invention can also be applied to the case of ejecting liquids other than liquid medicines, such as general water, oil, ethanol, organic solvents, and dispersed solutions such as emulsions in non-liquid forms. The water used is not limited to water used in agriculture or gardening, for example, it can also be water used in the manufacture of medicines, water used in the manufacture of food, water used in the manufacture of cosmetics, water used in the manufacture of functional materials, water used in the aquaculture industry (especially aquaculture), cleaning water, and medical water. Moreover, the present invention can also be applied to the case of generating nanobubbles from these waters and ejecting them.

[0119] Description of Reference Numerals

[0120] 10. Liquid ejection device; 11. Ejection head; 12. Ejection port; 13. Liquid tank; 13a. Supply port; 13b. Discharge port; 13c. Return port; 14. Pump; 14a. Discharge port; 14b. Second discharge port; 15. Flow path; 16. Suction flow path; 17. First flow path; 18. Second flow path; 30. Microbubble generator; 31. Tubular portion; 32. Threaded teeth; 33. Small diameter portion; 34. Inlet; 35. Outlet; 36. Large diameter portion; 37. Reduced diameter part; 38, first small diameter part; 39, expanded diameter part; 40, same diameter part; 41, turbulence generating part; 42, second small diameter part; 43, ejection part; 44, load generating part; 45, step surface; 46, cylindrical convex part; 47, connecting part; 48, recessed part; 49, gas injection part; 51, first component; 52, second component; 53, 54, flange part; 60, microbubble generator; 100, vehicle with liquid ejection device; 110, air supply device; H, hose; V, opening and closing valve.

Claims

1. A liquid ejection device, wherein: The liquid ejection device comprises: One or more spray ports, the one or more spray ports spraying liquid; a dispensing device that dispenses liquid; a first flow path in which the liquid discharged from the discharge device flows toward the one or more discharge ports; as well as a microbubble generator disposed at a midway position of the first flow path, A small diameter portion is provided in the tubular portion of the microbubble generator, and the inner diameter of the small diameter portion is smaller than the inner diameter of the upstream side portion of the small diameter portion. The microbubble generator generates microbubbles in the liquid by cavitation generated when the liquid flowing in the tubular portion passes through the small diameter portion from the upstream side of the small diameter portion. The cross-sectional area of ​​the small diameter portion is equal to or larger than the total value of the opening areas of the one or more ejection ports.

2. The liquid ejection device according to claim 1, wherein: The liquid ejection device comprises a reservoir for storing liquid. The discharging device sucks in and discharges the liquid in the reservoir. The liquid ejecting device further comprises a second flow path connected to the first flow path at a position on the downstream side of the microbubble generator in the first flow path. The downstream end of the second flow path is connected to the reservoir.

3. The liquid ejection device according to claim 1, wherein: The small diameter portion includes a first small diameter portion and a second small diameter portion located downstream of the first small diameter portion. Inside the tubular portion, between the first small diameter portion and the second small diameter portion, there is provided: an expanded diameter portion, which is located on the downstream side of the first small diameter portion and has an inner diameter that increases toward the downstream side; a uniform diameter portion adjacent to the expanded diameter portion on the downstream side of the expanded diameter portion and extending toward the downstream side with an inner diameter having the same length as the inner diameter at the downstream end of the expanded diameter portion; as well as The turbulent flow generating portion is disposed between the uniform diameter portion and the second small diameter portion, is adjacent to the uniform diameter portion and the second small diameter portion, and extends toward the downstream side with an inner diameter being the same length as that of the uniform diameter portion.

4. The liquid ejection device according to claim 3, wherein: In the axial direction of the tubular portion, a step surface intersecting the axial direction is provided between the inner wall surface of the turbulent flow generating portion and the inner wall surface of the second small diameter portion.

5. The liquid ejection device according to claim 4, wherein: A cylindrical convex portion is provided in the turbulent flow generating portion, the cylindrical convex portion protruding toward the upstream side along the axial direction from a portion of the step surface surrounding the upstream end of the second small diameter portion, A recessed portion is provided between an inner wall surface of the turbulent flow generating portion and an outer peripheral surface of the cylindrical convex portion.

6. The liquid ejection device according to claim 1, wherein: The discharge pressure when the discharge device discharges the liquid is set so that the pressure of the liquid when passing through the upstream end of the microbubble generator in the first flow path is 0.15 MPa or more.

7. The liquid ejection device according to claim 1, wherein: The microbubble generator is composed of a nozzle, and the liquid containing microbubbles flows out from the top of the nozzle.

8. The liquid ejection device according to claim 1, wherein: Part of the first flow path is formed by a hose. A portion of the hose is connected to an end of the tubular portion of the microbubble generator.

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