Liquid injection nozzle and liquid injection device

Abstract

To provide a liquid jetting nozzle that can scatter droplets generated from split continuous flow of liquid jetted from a jetting hole of a jetting nozzle hole, with excellent straightness and jet the liquid as contracted flow.SOLUTION: A liquid jetting nozzle 11 comprises a jetting nozzle hole 1 and a liquid passage 29 which is larger in diameter than the jetting nozzle hole and is connected to the jetting nozzle hole, which makes droplets generated from split continuous flow 5 of liquid jetted from the jetting nozzle hole contact an object, where the jetting nozzle hole is formed in a cylindrical shape and a curvature radius R of an edge 31 at an inlet connected to the liquid passage of the jetting nozzle hole is equal to or less than 25% of a nozzle hole diameter d of the jetting nozzle hole.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a liquid ejection nozzle and a liquid ejection device that ejects liquid at high pressure toward an object to perform a predetermined process. [Background technology]

[0002] Conventionally, ultrasonic water jet devices are known that use piezoelectric elements to turn a continuous flow of high-pressure water into droplets and collide them with an object to perform processes such as cutting or cleaning the object (Patent Document 1). Also, a foaming nozzle structure capable of discharging a spray-like liquid by forming bubbles in a continuous flow is known (Patent Document 2). In this foaming nozzle structure, the rounded rear edge of each rib is formed into a circular shape as a whole with a radius R. Here, it is disclosed that if the width of the slot of radius R is S, the ratio R:S=1:2 to 1:4. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2007-523751 [Patent Document 2] Special Publication No. 4-500038 Summary of the Invention [Problem to be solved by the invention]

[0004] However, none of the above documents mentions the consideration of increasing the impact pressure of droplets produced by splitting a continuous flow of liquid ejected from the outlet of an ejection nozzle hole in a straight line by ejecting the liquid as a contracted flow. Furthermore, with the foaming nozzle structure of Patent Document 2, the spray is deflected in various directions, so it is possible to reliably spray a mist, but it is not possible to spray droplets in a straight line, making it difficult to increase the impact pressure of the droplets. [Means for solving the problem]

[0005] In order to solve the above problems, the liquid injection nozzle of the present invention has a injection nozzle hole and a liquid flow path that is larger in diameter than the injection nozzle hole and connects to the injection nozzle hole, and the continuous flow injected from the injection nozzle hole is converted into droplets, and the droplets are directed at an object, wherein the injection nozzle hole has a cylindrical shape, and the radius of curvature of the edge of the inlet of the injection nozzle hole that connects to the liquid flow path is 25% or less of the nozzle hole diameter of the injection nozzle hole.

[0006] Furthermore, the liquid injection device according to the present invention is a liquid injection device having a liquid injection nozzle which converts an injected continuous flow into droplets and causes the droplets to hit an object, and further comprising a pressurized liquid supply unit which pressurizes and supplies liquid to the liquid injection nozzle, the liquid injection nozzle having a injection nozzle hole and a liquid flow path which is larger in diameter than the injection nozzle hole and which is connected to the injection nozzle hole, the injection nozzle hole having a cylindrical shape, and a radius of curvature of an edge of the injection nozzle hole which connects to the liquid flow path which is 25% or less of the nozzle hole diameter of the injection nozzle hole. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic diagram illustrating the overall configuration of a liquid ejecting device including a liquid ejecting nozzle according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of a main part of the liquid injection nozzle according to the first embodiment. [Diagram 3] 13 is a graph showing the relationship between the analytical value / theoretical value (vertical axis) of the ejection velocity and the curvature radius R (horizontal axis) of the edge of the ejection nozzle hole when the nozzle hole diameter of the first embodiment is 0.12 mm. [Figure 4] 13 is a graph showing the relationship between the analytical value / theoretical value (vertical axis) of the ejection velocity and the curvature radius R (horizontal axis) of the edge of the ejection nozzle hole when the nozzle hole diameter of the first embodiment is 0.08 mm. [Diagram 5] 13 is a graph showing the relationship between the analytical value / theoretical value (vertical axis) of the ejection velocity and the curvature radius R (horizontal axis) of the edge of the ejection nozzle hole when the nozzle hole diameter of the first embodiment is 0.05 mm. [Figure 6] 13 is a graph showing the relationship between the analytical value of the ejection speed (vertical axis) and the curvature radius R (horizontal axis) of the edge of the ejection nozzle hole when the nozzle hole diameter of the second embodiment is 0.12 mm. [Figure 7] 13 is a graph showing the relationship between the analytical value of the ejection speed (vertical axis) and the curvature radius R (horizontal axis) of the edge of the ejection nozzle hole when the nozzle hole diameter of the second embodiment is 0.08 mm. [Figure 8] 13 is a graph showing the relationship between the analytical value of the ejection speed (vertical axis) and the curvature radius R (horizontal axis) of the edge of the ejection nozzle hole when the nozzle hole diameter of the second embodiment is 0.05 mm. [Figure 9] 13 is a graph showing the relationship between the analytical value / actual measurement value (vertical axis) of the ejection velocity and the curvature radius R (horizontal axis) of the edge of the ejection nozzle hole when the nozzle hole diameter of the second embodiment is 0.12 mm. [Figure 10] 13 is a graph showing the relationship between the analytical value / actual measurement value (vertical axis) of the ejection speed and the curvature radius R (horizontal axis) of the edge of the ejection nozzle hole when the nozzle hole diameter of the second embodiment is 0.08 mm. [Figure 11] 13 is a graph showing the relationship between the analytical value / actual measurement value (vertical axis) of the ejection speed and the curvature radius R (horizontal axis) of the edge of the ejection nozzle hole when the nozzle hole diameter of the second embodiment is 0.05 mm. [Figure 12] A high-speed image was obtained by using a high-speed camera to capture the flight trajectory of a droplet ejected from a nozzle hole. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention will first be briefly described below. In order to solve the above problems, a liquid injection nozzle according to a first aspect of the present invention is a liquid injection nozzle having a injection nozzle hole and a liquid flow path having a diameter larger than that of the injection nozzle hole and connected to the injection nozzle hole, the liquid injection nozzle directing the liquid droplets produced when a continuous flow injected from the injection nozzle hole is converted into droplets onto a target object, the injection nozzle hole being cylindrical in shape, and the radius of curvature of an edge of the injection nozzle hole which is connected to the liquid flow path is 25% or less of the nozzle hole diameter of the injection nozzle hole.

[0009] According to this aspect, the radius of curvature of the edge of the inlet of the ejection nozzle hole connected to the liquid flow path is 25% or less of the nozzle hole diameter of the ejection nozzle hole. This makes it possible to make the droplets formed by splitting the continuous flow of liquid ejected from the ejection port of the ejection nozzle hole fly with good straightness, and to eject the liquid as a contracted flow. By making the flow contract, the ejection speed is increased compared to when the flow is not contracted, and the impact pressure of the droplets can be increased accordingly.

[0010] In addition, it is said that the ease of forming the contracted flow is best when the radius of curvature of the edge of the injection nozzle hole is zero, i.e., exactly 90 degrees. However, it is difficult to create an injection nozzle hole whose edge has a radius of curvature of zero, so the aim is to create one with a radius of curvature as close to zero as possible. Under such circumstances, the inventors confirmed that there is a range in which a contracted flow can be formed even if the radius of curvature of the edge is not zero. In other words, it was confirmed that the contracted flow can be formed up to a certain range even if the radius of curvature of the edge is not zero. Furthermore, during this confirmation, it was discovered that the range in which the contracted flow can be formed becomes wider as the nozzle hole diameter becomes larger. In this embodiment, the "radius of curvature of the edge is 25% or less of the nozzle hole diameter of the injection nozzle hole" is based on the above discovery. As a result, according to this aspect, when manufacturing an injection nozzle hole capable of forming the contraction flow, it is no longer necessary to be conscious of vaguely aiming to make the radius of curvature of the edge zero; in other words, it is possible to grasp the size of the radius of curvature that is actually required depending on the nozzle hole diameter of the injection nozzle hole, thereby making manufacturing easier.

[0011] The liquid jet nozzle according to a second aspect of the present invention is the liquid jet nozzle of the first aspect, characterized in that the radius of curvature of the edge is in the range of 5% to 10% of the nozzle hole diameter.

[0012] According to this aspect, the radius of curvature of the edge is in the range of 5% to 10% of the nozzle hole diameter. If it is 5% or more, the difficulty of manufacturing is unlikely to be an issue. Also, if it is 10% or less, the probability that the nozzle hole diameter can form a contracted flow over a wide range is higher than in the case of 25%. This makes it possible to provide a liquid ejection nozzle that is highly reliable in forming a contracted flow, with ease of manufacturing.

[0013] The liquid jet nozzle according to a third aspect of the present invention is the liquid jet nozzle according to the first or second aspect, characterized in that the nozzle hole diameter is in the range of 0.01 mm to 0.15 mm.

[0014] According to this aspect, it has been confirmed that the contracted flow can be formed for liquid-jet nozzle holes having a nozzle hole diameter in the range of 0.01 mm to 0.15 mm.

[0015] A liquid injection device according to a fourth aspect of the present invention is a liquid injection device having a liquid injection nozzle that converts an injected continuous flow into droplets and applies the resulting droplets to an object, and further comprising a pressurized liquid supply unit that pressurizes and supplies liquid to the liquid injection nozzle, the liquid injection nozzle being characterized in that it is any one of the first to third aspects.

[0016] According to this aspect, as a liquid ejecting device, it is possible to obtain the same effects as any one of the first to third aspects.

[0017] [Embodiment 1] A liquid ejection device including a liquid ejection nozzle according to a first embodiment of the present invention will be described in detail below with reference to Fig. 1 to Fig. 5. This liquid ejection device is a liquid ejection device for skin cleansing that is required to eject liquid droplets with good straightness from the end face on the ejection side of the ejection nozzle hole. Of course, the liquid ejecting device is not limited to the above-mentioned device, and can also be applied to a dental treatment device or the like.

[0018] As shown in FIG. 1, the liquid injection device 25 according to this embodiment includes an injection section 2 having a liquid injection nozzle 11 for injecting liquid 3, a liquid tank 6 for storing the liquid 3 to be injected, a pump unit 27 which is a pressurized liquid supply section, a liquid suction tube 12 which forms a flow path 10 for the liquid 3 connecting the liquid tank 6 and the pump unit 27, and a liquid delivery tube 14 which also forms the flow path 10 connecting the pump unit 27 and the injection section 2. In the pump unit 27, the pump operation such as the pressure of the liquid 3 sent to the ejection part 2 through the liquid sending tube 14 is controlled by the control part 4.

[0019] <Liquid injection nozzle> The liquid jet nozzle 11 has one or more jet nozzle holes 1, and high-pressure liquid 3 is jetted from the jet nozzle holes 1. In the partially enlarged view of Fig. 1, the symbol F indicates the liquid jet direction. The high-pressure liquid 3 sprayed from the spray nozzle hole 1 is a continuous flow 5 immediately after spraying, but is quickly broken into droplets by the surface tension of the liquid 3 and split into a group of droplets 7. The group of droplets 7 flies aligned in a straight line in the liquid spray direction F. The group of flying droplets 7 is caused to hit an object 9 one after another to perform a predetermined process. In the partially enlarged view of FIG. 1, the dimensions of the droplets 7 and the continuous stream 5 are greatly enlarged relative to other components in order to make the drawing easier to understand, and their actual relative dimensional relationships are ignored.

[0020] 2, the liquid jet nozzle 11 has a jet nozzle hole 1 and a liquid flow path 29 that is larger in diameter than the jet nozzle hole 1 and connects to the jet nozzle hole 1, and the continuous flow 5 jetted from the jet nozzle hole 1 is converted into droplets, producing liquid droplets 7 that hit an object 9. The jet nozzle hole 1 has a cylindrical shape. Furthermore, the radius of curvature R of an edge 31, which is the edge of the entrance of the jet nozzle hole 1 that connects to the liquid flow path 29, is set to 25% or less of the nozzle hole diameter d of the jet nozzle hole 1. That is, the radius of curvature R of the edge 31 is set in relation to the nozzle hole diameter d of the injection nozzle hole 1, and is set within a range in which R / d is 25% or less. 2, reference numeral 20 denotes a hole wall surface of the injection nozzle hole 1, and reference numeral 22 denotes an injection port. The hole wall surface 20 is cylindrical with a diameter d, and the injection port 22 is circular with a diameter d.

[0021] <contraction flow> Fig. 2 shows the state in which the liquid 3 is injected from the injection nozzle hole 1 as a contracted flow 18. The contracted flow 18 is a state in which the continuous flow 5 injected from the injection nozzle hole 1 has a gap between it and the hole wall surface 20, that is, the liquid is injected without contacting the hole wall surface 20, as shown in Fig. 2. In other words, the contracted flow 18 is a state in which the continuous flow 5 is injected as a flow having a diameter smaller than the nozzle hole diameter d. As a result, it is known that the injection speed V in the contracted flow state is faster than the continuous flow injected in a non-contracted flow state.

[0022] In this embodiment, the liquid flow path 29 is also formed in a cylindrical shape. Note that the liquid flow path 29 is not limited to a cylindrical shape, and may be in the shape of a polygonal tube. In addition, in this embodiment, the flight trajectory of the center 15 of the droplet 7 is configured to be within a range of radius r of 0.5 mm from the central axis 17 of the ejection nozzle hole 1, within a predetermined distance from the end face 13 on the ejection side of the ejection nozzle hole 1.

[0023] <Nozzle hole diameter and droplet size> In this embodiment, the nozzle hole diameter d of the injection nozzle hole 1 is set in the range of 0.01 mm to 0.15 mm. It is known that the size of the droplets 7 is approximately 1.88 times the nozzle hole diameter d from the linear theory of non-viscosity. Since the nozzle hole diameter d of the injection nozzle hole 1 is 0.01 mm to 0.15 mm, the droplet size is calculated to be 0.0188 mm to 0.282 mm. Furthermore, considering that the droplet size varies somewhat depending on the smoothness of the injection nozzle hole 1, the droplet size is approximately 0.02 mm to 0.29 mm as the average droplet diameter. Here, since most of the droplets 7 are not actually perfectly spherical but are deformed into an ellipse or the like, the "average droplet diameter" is calculated as the average value based on the longest diameter part and the shortest diameter part.

[0024] <Injection pressure> In the liquid jetting device 25 according to this embodiment, the pump unit 27 which is a pressurized liquid supply section is configured to supply the liquid 3 at a supply pressure such that the jetting pressure of the liquid 3 jetted from the jet nozzle hole 1 is 0.2 MPa to 10 MPa. The control unit 4 sets the injection pressure so that the injection velocity V of the liquid 3 injected from the injection nozzle hole 1 becomes a predetermined velocity. Once the injection velocity V is determined, the speed of the flying droplets 7 is also determined. The speed of the droplets 7 is the same as the injection velocity V until the effect of air resistance appears, and the droplets fly at the velocity V.

[0025] <Explanation that the edge curvature radius R is 25% or less of the nozzle hole diameter d> (1) From the "analytical value / theoretical value" of the injection velocity V FIG. 3 is a graph showing the relationship between the analytical / theoretical value of the ejection velocity V and the curvature radius R of the edge 31 of the ejection nozzle hole 1 when the nozzle hole diameter d is 0.12 mm. Here, the "analytical value" of the jet velocity V (m / s) is the value obtained for each set flow rate (ml / min) of 50, 70, and 90 of the liquid 3 using general-purpose three-dimensional thermal fluid analysis software (FLOW-3D). Also, the "theoretical value" is the theoretical velocity (m / s) determined by dividing each set flow rate (ml / min) of 50, 70, and 90 of the liquid 3 by the nozzle cross-sectional area of ​​each jet nozzle hole 1 for each nozzle hole diameter d. The left part of Table 1 shows that for an injection nozzle hole 1 with a nozzle hole diameter of 0.12 mm, the corresponding theoretical velocities (m / s) when the set flow rates (ml / min) of liquid 3 are 50, 70, and 90, i.e., the "theoretical values", are 74, 103, and 133.

[0026] FIG. 4 is a graph showing the relationship between the analytical / theoretical value of the ejection velocity V and the curvature radius R of the edge 31 of the ejection nozzle hole 1 when the nozzle hole diameter is 0.08 mm. The "analysis values" are values ​​obtained for set flow rates (ml / min) of 20, 30, and 40 for the liquid 3 using the three-dimensional thermal fluid analysis software. The central part of Table 1 shows that for an injection nozzle hole 1 with a nozzle hole diameter of 0.08 mm, the corresponding theoretical velocities (m / s) when the set flow rates (ml / min) of liquid 3 are 20, 30, and 40, i.e., the "theoretical values", are 66, 99, and 133.

[0027] FIG. 5 is a graph showing the relationship between the analytical / theoretical value of the ejection velocity V and the curvature radius R of the edge 31 of the ejection nozzle hole 1 when the nozzle hole diameter is 0.05 mm. The "analysis values" are values ​​obtained for the set flow rates (ml / min) 8, 12, and 14 of the liquid 3 using the three-dimensional thermal fluid analysis software. The right part of Table 1 shows that for an injection nozzle hole 1 with a nozzle hole diameter of 0.05 mm, the corresponding theoretical velocities (m / s) when the set flow rates (ml / min) of liquid 3 are 8, 12, and 14, i.e., the "theoretical values", are 68, 102, and 119.

[0028] [Table 1]

[0029] In Figure 3, if the ratio of the "analysis value" of the injection velocity V to the "theoretical value", "analysis value / theoretical value", exceeds at least 1.1, the injection velocity V is 1.1 times faster than the theoretical velocity, i.e., 10% faster. This state can be considered as the formation of a contraction flow. In Figure 3, when the nozzle hole diameter d is 0.12 mm, the radius of curvature R of the edge 31 is 0.06 mm, exceeding 1.1. In this case, R / d is 0.06 / 0.12 x 100 = 50%. When the nozzle hole diameter d is 0.12 mm, a contracted flow is formed even if the radius of curvature R is not reduced to the extent that R / d becomes 25%. It can be said that when the nozzle hole diameter d is 0.12 mm, the allowable range of the radius of curvature R for forming a contracted flow is wider.

[0030] In Figure 4, when the nozzle hole diameter d is 0.08 mm, the radius of curvature R of the edge 31 is 0.04 mm, exceeding 1.1. In this case, R / d is 0.04 / 0.08 x 100 = 50%. Even when the nozzle hole diameter d is 0.08 mm, a contracted flow is formed without reducing the radius of curvature R to the point where R / d is 25%. It can be said that the permissible range of the radius of curvature R for forming a contracted flow is wide, even when the nozzle hole diameter d is 0.08 mm.

[0031] In Fig. 5, when the nozzle hole diameter d is 0.05 mm, the radius of curvature R of the edge 31 is 0.0125 mm, which exceeds 1.1. In this case, R / d is 0.0125 / 0.05 x 100 = 25%. When the nozzle diameter is 0.05 mm, R / d is 25%, so a contraction is formed.

[0032] From the above, it can be seen that for the injection nozzle hole 1 with a nozzle hole diameter d of 0.12 mm, 0.08 mm, or 0.05 mm, if the nozzle hole diameter d is designed so that R / d is 25% or less, a contracted flow will be formed. Furthermore, it can be seen that for the nozzle hole diameters d of 0.12 mm and 0.08 mm, a contracted flow will be formed even if R / d is 50%. In addition, similar data was obtained and a similar study was performed for the nozzle hole diameter d of the injection nozzle hole 1 of 0.15 mm and 0.01 mm. As a result, it was confirmed that a contraction flow can be formed if R / d is made to be 25% or less in either case.

[0033] Table 2 shows the theoretical velocity ratio, which is the ratio of the "actual value" of the injection velocity V to the "theoretical value" mentioned above, for nozzle hole diameters d of 0.12 mm, 0.08 mm, and 0.05 mm, calculated for each flow rate (ml / min) in Table 2. When the nozzle hole diameter d is 0.12 mm, R / d is 1.7%, when it is 0.08 mm, R / d is 1.3%, and when it is 0.05 mm, R / d is 2.0%. The actual measurement of the ejection velocity V was obtained as follows. <Measured value of injection velocity V> Figure 12 shows high-speed images taken with a high-speed camera of the flight trajectory of a droplet 7 ejected from the ejection nozzle hole 1 and flying at a speed V. Two or three images (three in the figure) were selected, and the travel distance S of the droplet 7 in question was calculated. This was then divided by the time interval between images to determine the speed of the droplet, which was used as the actual measurement of the ejection speed V.

[0034] Specifically, the approximate value of R was determined from Figs. 3 to 5, and the value of R / d obtained from that was used as the actual measurement value. When the nozzle hole diameter d is 0.12 mm, the theoretical velocity ratios are 1.40, 1.35, and 1.28, so the average value is approximately 1.34. From Figure 3, the value of R at this time is approximately 0.002 mm, so R / d = 0.002 / 0.12 = 0.0166... ​​≒ 1.7%. When the nozzle hole diameter d is 0.08 mm, the theoretical velocity ratios are 1.44, 1.42, and 1.35, so the average value is approximately 1.41. In Figure 4, none of these values ​​reach 1.41, so the value of R where the analytical value / theoretical value is maximum is used, and as the value of R is approximately 0.001 mm, R / d = 0.001 / 0.08 = 0.0125... ≒ 1.3%. When the nozzle hole diameter d is 0.05 mm, the theoretical velocity ratios are 1.36, 1.35, and 1.31, so the average value is approximately 1.34. From Figure 5, the value of R at this time is approximately 0.001 mm or approximately 0.004 mm, so 0.001 mm was adopted in consideration of consistency with the above. Therefore, R / d = 0.001 / 0.05 = 0.02 ≒ 2.0%.

[0035] [Table 2]

[0036] In Table 2, the minimum theoretical velocity ratio, which is the ratio of the measured value of the injection velocity V to the theoretical value, varies depending on the nozzle hole diameter d, but is 1.28 when d is 0.12 mm, 1.35 when d is 0.08 mm, and 1.31 when d is 0.05 mm. Therefore, it can be seen that the measured injection velocity V is faster than the theoretical velocity in all the injection nozzle holes 1. In other words, a contraction flow is formed. Furthermore, similar studies were carried out on nozzle holes 1 with a nozzle hole diameter d of 0.15 mm and 0.01 mm, obtaining data on actual measurements and theoretical values. As a result, it was confirmed that a contraction flow would be formed if R / d was set to 25% or less in either case.

[0037] <Explanation of Effects of First Embodiment> According to this embodiment, the radius of curvature R of the edge 31 of the inlet connected to the liquid flow path 29 of the jet nozzle hole 1 is 25% or less of the nozzle hole diameter d of the jet nozzle hole 1, i.e., R / d is 25% or less. This makes it possible to cause the droplets 7 formed by splitting the continuous flow 5 of the liquid 3 jetted from the jet outlet 22 of the jet nozzle hole 1 to fly in a straight line, and also makes it possible to jet the liquid 3 as a contracted flow 18. By forming the contraction flow 18, the ejection velocity V becomes higher than when there is no contraction flow, and the impact pressure of the droplets 7 can be increased accordingly.

[0038] It is said that the ease of forming the contraction flow 18 is better when the radius of curvature R of the edge 31 of the injection nozzle hole 1 is zero, that is, exactly 90 degrees. However, it is difficult to create an injection nozzle hole 1 whose edge 31 has a radius of curvature R of zero, so the aim is to create one with a radius of curvature R as close to zero as possible. The inventors have confirmed that there is a range in which the contracted flow 18 can be formed even if the radius of curvature R of the edge 31 is not zero. In other words, they have confirmed that the contracted flow 18 can be formed up to a certain range even if the radius of curvature R of the edge 31 is not zero. Furthermore, during this confirmation, they discovered that the range in which the contracted flow 18 can be formed increases as the nozzle hole diameter d increases. In this embodiment, the "radius of curvature R of the edge 31 is 25% or less of the nozzle hole diameter d of the injection nozzle hole 1d" is based on this discovery. As a result, according to this embodiment, when manufacturing an injection nozzle hole 1 capable of forming a contraction flow 18, it is no longer necessary to aim vaguely for the radius of curvature R of the edge 31 to be zero. In other words, it is possible to grasp the size of the radius of curvature R that is actually required according to the nozzle hole diameter d of the injection nozzle hole 1, thereby facilitating manufacturing.

[0039] [Embodiment 2] Next, a liquid jet nozzle 1 according to a second embodiment of the present invention will be described with reference to Figures 6 to 11. In Figures 6 to 8, a number of dashed lines indicate reference values ​​for each flow rate. In this embodiment, the ratio R / d of the radius of curvature R of the edge 31 to the nozzle hole diameter d is set to be in the range of 5% to 10%.

[0040] <Explanation that the radius of curvature R of the edge is in the range of 5% to 10% of the nozzle hole diameter d> (1) From the "analysis value / reference value" of the injection velocity V Fig. 6 is a graph comparing analytical values ​​and reference values ​​of the ejection velocity V versus the curvature radius R of the edge 31 of the ejection nozzle hole 1 when the nozzle hole diameter d is 0.12 mm. The set flow rates (ml / min) of the liquid 3 are 50, 70, and 90. Here, the "analytical value" of the jet velocity V (m / s) is the same as above. For the "reference value", the analytical value of the jet velocity when the radius of curvature R of the edge 31 is 0, in other words, when the edge 31 forms a right angle, was found and used as the reference value. The state in which the edge 31 forms a right angle can be said to be advantageous for forming the contraction flow 18, so this was used as the reference value. The "reference value", which is the analytical value of the jet velocity when the radius of curvature R forms a right angle, was found as follows. <How to calculate the standard value> Using an analytical model created by setting the edge 31 shown in FIG. 2 at a right angle, the injection speed at each set flow rate (ml / min) was calculated using the above-mentioned three-dimensional thermal fluid analysis software.

[0041] 7 is a graph showing the relationship between the analytical value / reference value of the ejection velocity V and the curvature radius R of the edge 31 of the ejection nozzle hole 1 when the nozzle hole diameter d is 0.08 mm. The set flow rates (ml / min) of the liquid 3 are 20, 30, and 40. 8 is a graph showing the relationship between the analytical value / reference value of the ejection velocity V and the curvature radius R of the edge 31 of the ejection nozzle hole 1 when the nozzle hole diameter d is 0.05 mm. The set flow rates (ml / min) of the liquid 3 are 8, 12, and 14.

[0042] 6, when the nozzle hole diameter d is 0.12 mm, the radius of curvature R of the edge 31 is 0.012 mm, which exceeds the reference value. In this case, R / d is 0.012 / 0.12×100=10%. 7, when the nozzle hole diameter d is 0.08 mm, the radius of curvature R of the edge 31 is 0.008 mm, which exceeds the reference value. In this case, R / d is 0.008 / 0.08×100=10%. 8, when the nozzle hole diameter d is 0.05 mm, the radius of curvature R of the edge 31 exceeds the reference value at 0.005 mm. In this case, R / d is 0.005 / 0.05×100=10%.

[0043] From the above, it can be seen that for injection nozzle holes 1 with nozzle hole diameters d of 0.12 mm, 0.08 mm, and 0.05 mm, the probability of the contraction flow 18 being formed is increased by making R / d 10% or less.

[0044] (2) From the "analysis value / measurement value" of the injection velocity V 9 is a graph showing the relationship between the analytical value / actual measurement value of the ejection velocity V and the curvature radius R of the edge 31 of the ejection nozzle hole 1 when the nozzle hole diameter d is 0.12 mm. The set flow rates (ml / min) of the liquid 3 are 50, 70, and 90. Here, the "analytical value" and "measured value" of the injection velocity V (m / s) are the same as above.

[0045] 10 is a graph showing the relationship between the analytical value / actual measurement value of the ejection velocity V and the curvature radius R of the edge 31 of the ejection nozzle hole 1 when the nozzle hole diameter d is 0.08 mm. The set flow rates (ml / min) of the liquid 3 are 20, 30, and 40. 11 is a graph showing the relationship between the analytical value / actual measurement value of the ejection velocity V and the curvature radius R of the edge 31 of the ejection nozzle hole 1 when the nozzle hole diameter d is 0.05 mm. The set flow rates (ml / min) of the liquid 3 are 8, 12, and 14.

[0046] 9, when the nozzle hole diameter d is 0.12 mm, the radius of curvature R of the edge 31 is 0.006 mm, which is almost greater than 1, for all flow rates (ml / min) of the liquid 3. In this case, R / d is 0.006 / 0.12×100=5%. 10, when the nozzle hole diameter d is 0.08 mm, the radius of curvature R of the edge 31 is 0.004 mm, which is almost greater than 1, for all flow rates (ml / min) of the liquid 3. In this case, R / d is 0.004 / 0.08×100=5%. 11, when the nozzle hole diameter d is 0.05 mm, the radius of curvature R of the edge 31 is 0.0025 mm, which is almost greater than 1, for all flow rates (ml / min) of the liquid 3. In this case, R / d is 0.0025 / 0.05×100=5%.

[0047] From the above, it can be seen that for injection nozzle holes 1 with nozzle hole diameters d of 0.12 mm, 0.08 mm, and 0.05 mm, the probability of the contraction 18 being formed is increased by making R / d 5%. That is, if the radius of curvature R of the edge 31 of the injection nozzle hole 1 is set to 5% of the nozzle hole diameter d, it can be said that the contraction flow 18 can be reliably formed. In addition, the injection velocity V is amplified to about 1.3 times the theoretical velocity, which means that an impact pressure 1.3 times stronger than theoretical can be generated, and high crushing and cleaning effects can be expected. In other words, the desired impact pressure determined by the ejection velocity V can be generated with a flow rate (ml / min) of liquid 3 that is approximately 30% less than theoretically possible, thereby enabling the flow rate of the ejected liquid 3 to be reduced.

[0048] According to this embodiment, the radius of curvature R of the edge 31 is in the range of 5% to 10% of the nozzle hole diameter d. If R / d is 5% or more, the difficulty of manufacturing is unlikely to be an issue. Also, if R / d is 10% or less, the probability that the nozzle hole diameter d can form the contracted flow 18 over a wide range is higher than in the case of 25%. This makes it possible to provide a liquid injection nozzle 11 that is easily manufactured and has a high degree of certainty in forming the contracted flow 18.

[0049] Other Embodiments The liquid injection nozzle 1 and liquid injection device 25 according to the embodiment of the present invention are based on the configuration as described above, but it is of course possible to modify or omit some parts of the configuration without departing from the gist of the present invention. [Explanation of symbols]

[0050] 1 injection nozzle hole, 2 injection part, 3 liquid, 4 control part, 5 continuous flow, 6 liquid tank, 7 droplet, 9 object, 10 flow path, 11 liquid injection nozzle, 12 liquid suction tube, 14 liquid delivery tube, 15 center, 17 central axis, 20 hole wall surface, 21 liquid inlet, 22 injection port, 25 liquid injection device, 27 pressurized liquid supply unit (pump unit), 29 liquid flow path, 31 edge F Liquid injection direction, R Radius of curvature, d Nozzle hole diameter

Claims

1. An injection nozzle hole; a liquid flow path having a diameter larger than that of the ejection nozzle hole and connected to the ejection nozzle hole, A liquid injection nozzle that converts a continuous flow injected from the injection nozzle hole into droplets and applies the droplets to an object, The injection nozzle hole is cylindrical, The radius of curvature of the edge of the inlet of the injection nozzle hole connected to the liquid flow path is in the range of 5% to 10% of the nozzle hole diameter of the injection nozzle hole. A liquid injection nozzle.

2. The liquid injection nozzle according to claim 1, The nozzle hole diameter is in the range of 0.01 mm to 0.15 mm. A liquid injection nozzle.

3. The liquid injection nozzle according to claim 1, The diameter of the continuous flow injected from the injection nozzle hole is smaller than the nozzle hole diameter. A liquid injection nozzle.

4. The liquid injection nozzle according to claim 3, The average droplet diameter of the droplets is larger than the nozzle hole diameter. A liquid injection nozzle.

5. The liquid injection nozzle according to claim 4, a velocity of the continuous flow injected from the injection nozzle hole is faster than a velocity of the liquid flowing through the liquid flow path; A liquid injection nozzle.

6. A liquid ejection device including a liquid ejection nozzle that ejects a continuous flow of liquid into droplets and ejects the droplets onto a target object, a pressurized liquid supply unit that pressurizes and supplies liquid to the liquid ejection nozzle, The liquid injection nozzle is as defined in any one of claims 1 to 5. A liquid ejection apparatus comprising:

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