JP2024118636A - nozzle - Google Patents

Abstract

To provide a nozzle capable of preventing foreign matter from adhering to a tip of the nozzle.SOLUTION: A nozzle 1 has a radial direction, and an axial direction extending from a base end side to a tip side, and sprays a gas-liquid mixture fluid from the tip side. The tip of the nozzle 1 includes: a central flow passage 3 including a liquid outlet 4 at a tip thereof; a first outer peripheral flow passage 6 formed around the central flow passage 3 and including a first gas outlet 7 at a tip thereof; and a second outer peripheral flow passage 9 formed around the first outer peripheral flow passage 6 and including a second gas outlet 10 at a tip thereof. When viewed from the nozzle tip side, the liquid outlet 4 is located on a radially inner side of the first gas outlet 7; the first gas outlet 7 is located on a radially inner side of the second gas outlet 10; and the second outer peripheral flow passage 9 includes a tip inclined portion 11 that is inclined radially inward toward the nozzle tip.SELECTED DRAWING: Figure 4

Description

The present invention relates to a nozzle, and more particularly to a two-fluid nozzle.

A variety of two-fluid nozzles that mix and spray liquid and gas are known in the art (e.g., Patent Documents 1 to 6).

JP 2016-093773 A JP 2008-018400 A JP 2006-167601 A JP 2004-237206 A JP 2001-149822 A JP 2000-107651 A

A two-fluid nozzle sprays a gas-liquid mixture from the tip of the nozzle, but continued use of the nozzle can cause foreign matter such as dust and powder to adhere to the tip of the nozzle, resulting in clogging. In this case, frequent maintenance of the nozzle may be required, liquid may drip from the nozzle tip, or it may become difficult to spray liquid from the nozzle as desired. The present invention was made in consideration of the above circumstances, and its purpose is to provide a nozzle that can prevent foreign matter from adhering to the nozzle tip.

The nozzle of the present invention that can solve the above problems is as follows.
[1] A nozzle having an axial direction and a radial direction extending from a base end side to a tip end side, which ejects a gas-liquid mixture fluid from the tip end side,
a tip portion of the nozzle has a central flow passage having a liquid outlet at its tip, a first outer peripheral flow passage formed around the central flow passage and having a first gas outlet at its tip, and a second outer peripheral flow passage formed around the first outer peripheral flow passage and having a second gas outlet at its tip,
When viewed from a nozzle tip side, the liquid outlet is located radially inward from the first gas outlet, and the first gas outlet is located radially inward from the second gas outlet,
The nozzle according to claim 1, wherein the second outer peripheral flow passage has a tip inclined portion that is inclined radially inward toward the tip of the nozzle.
[2] The nozzle according to [1], wherein a radially outer edge of the second gas outlet is located closer to the nozzle tip than a radially outer edge of the first gas outlet.
[3] The nozzle according to [1] or [2], wherein the outer edge of the liquid outlet is not located closer to the nozzle tip than the radially outer outer edge of the second gas outlet.
[4] The nozzle described in any of [1] to [3], wherein the first outer circumferential flow passage has a straight tip portion extending from the first gas outlet toward the base end, and the straight tip portion is formed so that a radially outer surface of the first outer circumferential flow passage extends approximately parallel to the axial direction.
[5] The nozzle according to [4], wherein in a cross section along the axial direction, the flow passage width of the tip inclined portion is wider than the flow passage width of the tip straight portion.
[6] The nozzle according to any one of [1] to [5], wherein the first outer peripheral flow passage is partially blocked when viewed from the nozzle tip side.
[7] The nozzle according to any one of [1] to [6], wherein the nozzle has a recessed portion in a surface on a tip side, and the second gas outlet is formed in the recessed portion.
[8] The nozzle according to any one of [1] to [7], wherein a pressure of the gas at the first gas outlet is higher than a pressure of the gas at the second gas outlet.
[9] The nozzle described in any of [1] to [8], wherein an upstream side of the second outer periphery flow passage is connected to the first outer periphery flow passage via an orifice, and gas supplied to the first outer periphery flow passage is ejected from the first gas outlet through the first outer periphery flow passage, and is also supplied to the second outer periphery flow passage through the orifice and ejected from the second gas outlet through the second outer periphery flow passage.
[10] The nozzle described in [9], wherein the second outer peripheral flow passage has an annular constriction portion centered in the axial direction between the tip inclined portion and the orifice, the constriction portion having a flow passage width narrower than that of the tip inclined portion.

In the nozzle of the present invention, liquid is ejected from a liquid outlet at the tip of the central flow path, and gas is ejected from a first gas outlet at the tip of a first outer peripheral flow path formed around the central flow path, and these are combined to eject a gas-liquid mixed fluid from the tip of the nozzle. The nozzle further ejects gas from a second gas outlet at the tip of a second outer peripheral flow path formed around the first outer peripheral flow path. Since the second outer peripheral flow path has a tip inclined portion that is inclined radially inward toward the nozzle tip, the gas ejected from the second gas outlet is ejected radially inward from the tip of the nozzle. Since the nozzle of the present invention is configured to eject gas from the second gas outlet in this way, it is possible to prevent foreign matter such as dust and powder from adhering to the tip of the nozzle.

1 shows an example of the configuration of a nozzle of the present invention, and is an axial cross-sectional view of the nozzle. 2 illustrates an enlarged cross-sectional view of the tip of the nozzle shown in FIG. 1 . 4 shows another example of the configuration of the nozzle of the present invention, and shows an axial cross-sectional view of the nozzle. 4 illustrates an enlarged cross-sectional view of the tip of the nozzle shown in FIG. 3 . FIG. 5 is a front view of the nozzle shown in FIGS. 1 to 4 as viewed from the tip side. 5 illustrates an enlarged cross-sectional view of a modified example of the tip of the nozzle shown in FIG. 4 . 5 illustrates an enlarged cross-sectional view of a modified example of the tip of the nozzle shown in FIG. 4 . 8 is a front view of the nozzle shown in FIG. 7 as viewed from the tip side.

The present invention relates to a nozzle that sprays a gas-liquid mixed fluid, i.e., a two-fluid nozzle. In a two-fluid nozzle, a gas-liquid mixed fluid is sprayed from the tip of the nozzle, but continued use of the nozzle may cause foreign matter such as dust and powder to adhere to the tip of the nozzle, resulting in clogging. The nozzle of the present invention is equipped with a nozzle tip purging function to prevent foreign matter from adhering to the nozzle tip and causing clogging. The nozzle of the present invention will be described below with reference to the drawings, but the present invention is not limited to the aspects shown in the drawings. Furthermore, the configuration of each nozzle can be arbitrarily replaced or combined.

Figures 1 to 8 show examples of the configuration of the nozzle of the present invention. Figure 1 shows an axial cross-sectional view of the nozzle according to the first embodiment, Figure 2 shows an enlarged cross-sectional view of the tip of the nozzle shown in Figure 1, Figure 3 shows an axial cross-sectional view of the nozzle according to the second embodiment, Figure 4 shows an enlarged cross-sectional view of the tip of the nozzle shown in Figure 3, Figure 5 shows a front view of the nozzle shown in Figures 1 to 4 as seen from the tip side, Figures 6 and 7 show enlarged cross-sectional views of modified examples of the tip of the nozzle shown in Figure 4, and Figure 8 shows a front view of the nozzle shown in Figure 7 as seen from the tip side.

The nozzle 1 has an axial direction extending from the base end side to the tip end side, and a radial direction, and ejects a gas-liquid mixed fluid from the tip end side. In the nozzle 1, the axial direction means the direction extending from the base end side to the tip end side of the nozzle 1. In Figs. 1 to 4, 6, and 7, the right side of the drawings corresponds to the base end side, and the left side of the drawings corresponds to the tip end side. The nozzle 1 has a central flow path 3 through which liquid flows, and the liquid flows through the central flow path 3 from the base end side to the tip end side. The nozzle 1 ejects a gas-liquid mixed fluid from the tip end side. The radial direction is a direction perpendicular to the axial direction, and means a direction extending radially from the center (centroid) of the central flow path 3 in a vertical cross section of the nozzle 1 in the axial direction. The nozzle 1 also has a circumferential direction as a direction surrounding the center (centroid) of the central flow path 3 in a vertical cross section of the nozzle 1 in the axial direction.

The nozzle 1 has a tip portion 2 as a portion including the tip of the nozzle 1. The tip portion 2 of the nozzle 1 has a central flow passage 3 having a liquid outlet 4 at its tip, a first outer peripheral flow passage 6 formed around the central flow passage 3 and having a first gas outlet 7 at its tip, and a second outer peripheral flow passage 9 formed around the first outer peripheral flow passage 6 and having a second gas outlet 10 at its tip. When viewed from the nozzle tip side, the liquid outlet 4 is located radially inward from the first gas outlet 7, and the first gas outlet 7 is located radially inward from the second gas outlet 10. The second outer peripheral flow passage 9 has a tip inclined portion 11 that is inclined radially inward toward the tip of the nozzle 1.

The tip 2 of the nozzle 1 has a triple-tube structure having an inner tube 21, a middle tube 22, and an outer tube 23. The tip 2 of the nozzle 1 can be defined as a portion having a triple-tube structure. A central flow passage 3 is formed in the internal space of the inner tube 21, a first outer peripheral flow passage 6 is formed in the space between the inner tube 21 and the middle tube 22, and a second outer peripheral flow passage 9 is formed in the space between the middle tube 22 and the outer tube 23. The tip of the inner tube 21 forms the outer edge of the liquid outlet 4, the tip of the middle tube 22 forms the outer edge of the radially outer side of the first gas outlet 7, and the tip of the outer tube 23 forms the outer edge of the radially outer side of the second gas outlet 10. When viewed from the nozzle tip side, the first gas outlet 7 is formed around the liquid outlet 4, and the second gas outlet 10 is formed around the first gas outlet 7.

The liquid to be sprayed from the tip of the nozzle 1 flows through the central flow passage 3. Examples of liquids to be sprayed from the nozzle 1 include water, medicinal liquids, paints, inks, and liquid seasonings. For example, a liquid delivery pump may be provided in communication with the base end side of the central flow passage 3, and liquid may be supplied to the central flow passage 3 by the liquid delivery pump. Alternatively, a liquid storage section may be provided at the base end side of the central flow passage 3, and the central flow passage 3 may be depressurized by the flow of gas ejected from the first gas outlet 7, and the liquid stored in the liquid storage section may be sucked into the central flow passage 3. In this way, the liquid is sprayed from the tip of the nozzle 1 together with the gas ejected from the first gas outlet 7.

The first peripheral flow passage 6 is used for gas that is ejected from the tip of the nozzle 1 together with the liquid as a gas-liquid mixed fluid, and the second peripheral flow passage 9 is used for gas that prevents foreign matter from adhering to the tip of the nozzle 1. Examples of gas that flow through the first peripheral flow passage 6 and the second peripheral flow passage 9 include air, nitrogen, argon, etc., but air is preferably used for simplicity. The gas is preferably introduced into the first peripheral flow passage 6 and the second peripheral flow passage 9 as a pressurized gas (e.g., compressed air). The pressurized gas is preferably introduced into the first peripheral flow passage 6 and/or the second peripheral flow passage 9 at a gauge pressure of, for example, 0.01 MPa to 0.8 MPa.

The gas introduced into the first peripheral flow passage 6 and the gas introduced into the second peripheral flow passage 9 may be the same or different, but for simplicity, it is preferable that they are the same. A gas supplying means such as a compressor is provided in communication with the base end side of the first peripheral flow passage 6 and the base end side of the second peripheral flow passage 9. The gas supplying means may be provided separately on the base end side of the first peripheral flow passage 6 and the base end side of the second peripheral flow passage 9, or the gas supplying means provided on the base end side of the first peripheral flow passage 6 may also serve as the gas supplying means provided on the base end side of the second peripheral flow passage 9.

In the nozzle 1A shown in Figures 1 and 2, the first outer peripheral flow passage 6 and the second outer peripheral flow passage 9 are formed independently inside the nozzle 1A, and gas is supplied separately to the first outer peripheral flow passage 6 and the second outer peripheral flow passage 9. In the nozzle 1A, a gas supply means may be provided on the base end side of the first outer peripheral flow passage 6 and the base end side of the second outer peripheral flow passage 9, respectively, or a common gas supply means may be provided on the base end side of the first outer peripheral flow passage 6 and the base end side of the second outer peripheral flow passage 9. On the other hand, in the nozzles 1B, 1C, and 1D shown in Figures 3, 4, 6, and 7, the first outer peripheral flow passage 6 and the second outer peripheral flow passage 9 are connected inside the nozzle 1, a gas supply means is provided on the base end side of the first outer peripheral flow passage 6, and the gas introduced into the first outer peripheral flow passage 6 is introduced into the second outer peripheral flow passage 9 inside the nozzle 1. Although not shown in the drawings, the nozzle 1 can also be configured such that a gas supply means is provided on the base end side of the second outer peripheral flow passage 9, and the gas introduced into the second outer peripheral flow passage 9 is introduced into the first outer peripheral flow passage 6 inside the nozzle 1.

The liquid flowing through the central flow passage 3 is ejected from the liquid outlet 4, and the gas flowing through the first outer peripheral flow passage 6 is ejected from the first gas outlet 7. These combine and collide, causing the liquid ejected from the liquid outlet 4 to be atomized, and a gas-liquid mixture fluid is ejected from the tip of the nozzle 1. The nozzle 1 also ejects gas from the second gas outlet 10 formed radially outward from the liquid outlet 4 and the first gas outlet 7. The second outer peripheral flow passage 9 has a tip inclined portion 11 that is inclined radially inward toward the tip of the nozzle 1, so that the gas ejected from the second gas outlet 10 is ejected radially inward from the tip of the nozzle 1. By ejecting gas from the second gas outlet 10 in this way, foreign matter such as dust and powder is less likely to adhere to the tip of the nozzle 1, for example, the liquid outlet 4 or the first gas outlet 7.

In the nozzle 1, the size of each outlet can be set appropriately. For example, referring to FIG. 5, the inner diameter of the liquid outlet 4, i.e., the inner diameter D1 of the tip of the inner tube 21, is preferably 0.2 mm or more, more preferably 0.3 mm or more, even more preferably 0.4 mm or more, and preferably 1.5 mm or less, more preferably 1.0 mm or less, and even more preferably 0.8 mm or less. The inner diameter D2 of the tip of the middle tube 22 that defines the outer edge of the radially outer side of the first gas outlet 7 is preferably 0.8 mm or more, more preferably 1.0 mm or more, even more preferably 1.2 mm or more, and preferably 2.5 mm or less, more preferably 2.2 mm or less, and even more preferably 2.0 mm or less. The inner diameter D3 of the tip of the outer tube 23 that defines the radially outer edge of the second gas outlet 10 is preferably 1.8 mm or more, more preferably 2.2 mm or more, even more preferably 2.5 mm or more, and preferably 5.0 mm or less, more preferably 4.5 mm or less, and even more preferably 4.0 mm or less.

The inner diameter D2 of the tip of the middle tube 22 that defines the outer edge of the first gas outlet 7 on the radially outer side is preferably 1.5 times or more, more preferably 2.0 times or more, and preferably 6.0 times or less, more preferably 5.0 times or less, and even more preferably 4.0 times or less, of the inner diameter of the liquid outlet 4, i.e., the inner diameter D1 of the tip of the inner tube 21. The inner diameter D3 of the tip of the outer tube 23 that defines the outer edge of the second gas outlet 10 on the radially outer side is preferably 1.5 times or more, more preferably 2.0 times or more, and preferably 8.0 times or less, more preferably 6.0 times or less, and even more preferably 4.5 times or less of the inner diameter D2 of the tip of the middle tube 22 that defines the outer edge of the first gas outlet 7 on the radially outer side.

The radial length of the first gas outlet 7 as viewed from the nozzle tip (length C1 between the inner tube 21 and the middle tube 22) is preferably 0.05 mm or more, more preferably 0.1 mm or more, and preferably 0.8 mm or less, more preferably 0.6 mm or less, and even more preferably 0.4 mm or less. The radial length of the second gas outlet 10 as viewed from the nozzle tip (length C2 between the middle tube 22 and the outer tube 23) is preferably 0.3 mm or more, more preferably 0.5 mm or more, and preferably 1.5 mm or less, more preferably 1.2 mm or less, and even more preferably 1.0 mm or less.

The radial length of the first gas outlet 7 as viewed from the nozzle tip (length C1 between the inner tube 21 and the middle tube 22) is preferably 0.2 times or more, more preferably 0.3 times or more, and preferably 1.5 times or less, more preferably 1.2 times or less, and even more preferably 1.0 times or less, of the inner diameter of the liquid outlet 4 (inner diameter D1 at the tip of the inner tube 21). The radial length of the second gas outlet 10 as viewed from the nozzle tip (length C2 between the middle tube 22 and the outer tube 23) is preferably longer than the radial length of the first gas outlet 7 as viewed from the nozzle tip (length C1 between the inner tube 21 and the middle tube 22). The radial length of the second gas outlet 10 as viewed from the nozzle tip (length C2 between the middle tube 22 and the outer tube 23) is preferably at least 1.2 times the radial length of the first gas outlet 7 as viewed from the nozzle tip (length C1 between the inner tube 21 and the middle tube 22), more preferably at least 1.5 times, and preferably at most 5.0 times, more preferably at most 4.0 times, and even more preferably at most 3.0 times.

In the nozzle 1, the axial position of each nozzle may be set as appropriate, but the tip of the inner tube 21 that defines the liquid nozzle 4, the tip of the middle tube 22 that defines the radially outer edge of the first gas nozzle 7, and the tip of the outer tube 23 that defines the radially outer edge of the second gas nozzle 10 are preferably located within a range of 3.0 mm in the axial direction, more preferably within a range of 2.5 mm, and even more preferably within a range of 2.0 mm.

In order to make it more difficult for foreign matter to adhere to the tip of the nozzle 1 by ejecting gas from the second gas outlet 10, it is preferable that the radially outer edge of the second gas outlet 10 is located closer to the nozzle tip than the radially outer edge of the first gas outlet 7. By configuring the tip 2 of the nozzle 1 in this manner, it is possible to prevent foreign matter from adhering to the radially inner surface of the first gas outlet 7 and the second outer peripheral flow path 9. In this case, the radially outer edge of the second gas outlet 10 is preferably located 0.1 mm or more, more preferably 0.2 mm or more, and even more preferably 0.3 mm or more closer to the nozzle tip than the radially outer edge of the first gas outlet 7, and is preferably located 3.0 mm or less, more preferably 2.0 mm or less, even more preferably 1.5 mm or less, and even more preferably 1.0 mm or less closer to the nozzle tip.

The outer edge of the liquid outlet 4 is preferably not located closer to the nozzle tip than the radially outer edge of the second gas outlet 10. By configuring the tip 2 of the nozzle 1 in this manner, adhesion of foreign matter to the liquid outlet 4 can be suppressed. For example, the radially outer edge of the second gas outlet 10 is preferably located 3.0 mm or less, more preferably 2.0 mm or less, even more preferably 1.5 mm or less, and even more preferably 1.0 mm or less closer to the nozzle tip than the outer edge of the liquid outlet 4.

The outer edge of the liquid outlet 4 may be located closer to the nozzle tip than the outer edge of the radially outer side of the first gas outlet 7, or closer to the nozzle base than the outer edge of the radially outer side of the first gas outlet 7. In the nozzles 1A, 1B, and 1D shown in Figures 1 to 4 and 7, the outer edge of the liquid outlet 4 is located closer to the nozzle tip than the outer edge of the radially outer side of the first gas outlet 7. The nozzles 1A, 1B, and 1D are so-called external mixing type two-fluid nozzles in which the liquid ejected from the liquid outlet 4 and the gas ejected from the first gas outlet 7 mix outside the first gas outlet 7. On the other hand, in the nozzle 1C shown in Figure 6, the outer edge of the liquid outlet 4 is located closer to the nozzle base than the outer edge of the radially outer side of the first gas outlet 7. Nozzle 1C is a so-called internal mixing type two-fluid nozzle in which the liquid ejected from the liquid ejection port 4 and the gas ejected from the first gas ejection port 7 are mixed inside the first gas ejection port 7.

When the nozzle 1 is an external mixing type two-fluid nozzle, i.e., when the outer edge of the liquid outlet 4 is located closer to the nozzle tip than the radially outer edge of the first gas outlet 7, the outer edge of the liquid outlet 4 is preferably located 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.3 mm or more closer to the nozzle tip than the radially outer edge of the first gas outlet 7, and is preferably 2.0 mm or less, more preferably 1.5 mm or less, even more preferably 1.0 mm or less, and even more preferably 0.7 mm or less closer to the nozzle tip. This makes it easier to prevent foreign matter from adhering to the liquid outlet 4.

On the other hand, when the nozzle 1 is an internal mixing type two-fluid nozzle, i.e., when the outer edge of the liquid outlet 4 is located closer to the nozzle base end than the radially outer edge of the first gas outlet 7, the outer edge of the liquid outlet 4 is preferably located 1.0 mm or less, more preferably 0.7 mm or less, even more preferably 0.5 mm or less, and even more preferably 0.3 mm or less closer to the nozzle base end than the radially outer edge of the first gas outlet 7. This makes it easier to prevent foreign matter from adhering to the liquid outlet 4.

The central flow passage 3 is preferably formed so as to extend from the liquid outlet 4 to the base end in a substantially parallel axial direction. For example, the central flow passage 3 preferably has a tip small diameter portion 5 that is substantially the same diameter as the liquid outlet 4 and extends from the liquid outlet 4 to the base end in a substantially parallel axial direction (see Figs. 2, 4, 6, and 7). On the base end side of the tip small diameter portion 5, the central flow passage 3 is preferably formed with a diameter larger than that of the tip small diameter portion 5. By forming the central flow passage 3 in this manner, it becomes easier to forcefully eject the liquid from the liquid outlet 4. The axial length of the tip small diameter portion 5 of the central flow passage 3 is preferably formed to be, for example, three times or more the inner diameter of the liquid outlet 4, and more preferably five times or more. There is no particular upper limit to the axial length of the tip small diameter portion 5 of the central flow passage 3, but in order to suppress pressure loss of the liquid at the tip small diameter portion 5, the axial length of the tip small diameter portion 5 is preferably 30 times or less, more preferably 20 times or less, and even more preferably 15 times or less, the inner diameter of the liquid outlet 4.

The first outer circumferential flow passage 6 has a tip straight portion 8 extending from the first gas outlet 7 to the base end side, and in the tip straight portion 8, the radially outer surface of the first outer circumferential flow passage 6 (i.e., the inner surface of the middle tube 22) is preferably formed so as to extend approximately parallel to the axial direction (see Figures 2, 4, 6, and 7). By forming the first outer circumferential flow passage 6 in this manner, the liquid ejected from the liquid outlet 4 is well mixed with the gas ejected from the first gas outlet 7, and is easily atomized by the shearing action of the gas ejected from the first gas outlet 7. As a result, it is possible to spray the liquid in droplets with a smaller particle size. In the first outer circumferential flow passage 6, the tip straight portion 8 is a portion formed so that the radially outer surface of the first outer circumferential flow passage 6 extends approximately parallel to the axial direction.

The axial length of the tip straight section 8 of the first outer circumferential flow passage 6 is preferably at least twice the radial length of the first gas outlet 7 as viewed from the nozzle tip side (length C1 between the inner tube 21 and the middle tube 22), and more preferably at least three times. There is no particular upper limit to the axial length of the tip straight section 8 of the first outer circumferential flow passage 6, but in order to reduce gas pressure loss at the tip straight section 8, the axial length of the tip straight section 8 is preferably no more than 15 times the radial length of the first gas outlet 7 as viewed from the nozzle tip side, more preferably no more than 10 times, and even more preferably no more than 5 times.

The radially inner surface of the first outer periphery flow passage 6 (i.e., the outer surface of the inner tube 21) is preferably formed so as to extend approximately parallel to the axial direction in the tip straight portion 8, or is formed so as to be inclined radially inward toward the nozzle tip. By forming the first outer periphery flow passage 6 in this way, the liquid ejected from the liquid ejection port 4 is easily atomized by the gas ejected from the first gas ejection port 7. It is more preferable that the radially inner surface of the first outer periphery flow passage 6 in the tip straight portion 8 has a portion formed so as to extend approximately parallel to the axial direction. For example, it is preferable that the radially inner surface of the first outer periphery flow passage 6 is formed so as to extend approximately parallel to the axial direction throughout the entire tip straight portion 8, or that the radially inner surface of the first outer periphery flow passage 6 is formed so as to be inclined radially inward toward the nozzle tip at the tip straight portion 8, and that the radially inner surface of the first outer periphery flow passage 6 is formed so as to extend approximately parallel to the axial direction at the base end side.

The first outer periphery flow passage 6 is preferably formed such that the flow passage width of the tip straight portion 8 is narrower than the flow passage width of the portion upstream of the tip straight portion 8 in a cross section along the axial direction. The flow passage width of the first outer periphery flow passage 6 means the width of the first outer periphery flow passage 6 in a direction perpendicular to the extension direction of the first outer periphery flow passage 6 in a cross section along the axial direction. If the first outer periphery flow passage 6 is formed in this way, the pressure loss of the gas flowing through the first outer periphery flow passage 6 can be kept small, and the shearing action of the liquid ejected from the liquid ejection port 4 by the gas ejected from the first gas ejection port 7 can be increased.

The first outer peripheral flow passage 6 may be formed at the tip 2 of the nozzle 1 approximately uniformly in the circumferential direction around the axial direction, but may also be formed with a part blocked as viewed from the nozzle tip side, and such a configuration example is shown in Figures 7 and 8. In the nozzle 1D shown in Figures 7 and 8, the first outer peripheral flow passage 6 is formed at the tip 2 of the nozzle 1 with a part blocked as viewed from the nozzle tip side. If the first outer peripheral flow passage 6 is formed in this way, the radial length of the first outer peripheral flow passage 6 (i.e., the clearance between the inner tube 21 and the middle tube 22) can be made long without changing the cross-sectional area of the first outer peripheral flow passage 6 in the direction perpendicular to the axial direction, and the first outer peripheral flow passage 6 can be made less likely to be clogged with foreign matter. In this case, it is preferable that the first outer peripheral flow passage 6 is partially blocked as viewed from the nozzle tip side at the tip straight portion 8.

Examples of partially blocking the first outer peripheral flow passage 6 include a mode in which a part of the outer surface of the inner tube 21 protrudes outward, a mode in which a part of the inner surface of the middle tube 22 protrudes inward, and a mode in which a spacer member is disposed between the outer surface of the inner tube 21 and the inner surface of the middle tube 22. In Figs. 7 and 8, a part of the outer surface of the inner tube 21 protrudes outward, thereby blocking a part of the first outer peripheral flow passage 6. Note that, in the portion upstream of the tip straight portion 8, the first outer peripheral flow passage 6 is preferably formed approximately evenly in the circumferential direction around the axial direction, i.e., formed axially symmetrically.

The second outer peripheral flow passage 9 has a tip inclined portion 11 that is inclined radially inward toward the nozzle tip. The tip inclined portion 11 is preferably formed surrounding the first gas outlet 7. By having the tip inclined portion 11 on the second outer peripheral flow passage 9, gas is ejected radially inward from the second gas outlet 10, and it is possible to prevent foreign matter such as dust and dirt from adhering to the liquid outlet 4, the first gas outlet 7, or their surroundings.

The tip inclined portion 11 is formed to extend obliquely with respect to the axial direction in a cross section along the axial direction of the nozzle 1. In a cross section along the axial direction of the nozzle 1, the angle between the extension direction of the tip inclined portion 11 and the axial direction is, for example, preferably 25° or more, more preferably 30° or more, even more preferably 35° or more, and preferably 65° or less, more preferably 60° or less, and even more preferably 55° or less. The extension direction of the tip inclined portion 11 can be determined based on the extension direction of the center line of the second outer peripheral flow passage 9 at the tip inclined portion 11 when viewed in a cross section along the axial direction.

In the tip inclined portion 11, it is preferable that the radially inner and outer surfaces of the second outer peripheral flow passage 9 are inclined radially inward toward the nozzle tip. It is preferable that the tip side of the tip inclined portion 11 of the second outer peripheral flow passage 9 faces the second gas outlet 10, and it is preferable that the radially inner surface of the second outer peripheral flow passage 9 extends at an inclination radially inward toward the nozzle tip and is connected to the radially inner outer edge of the second gas outlet 10 in the tip inclined portion 11. In other words, it is preferable that the radially inner surface of the second outer peripheral flow passage 9 is formed so that it extends at an inclination radially inward toward the nozzle tip to the radially inner outer edge of the second gas outlet 10. The radially outer surface of the second outer peripheral flow passage 9 may extend at an inward inclination toward the nozzle tip and connect to the radially outer edge of the second gas outlet 10, or may extend at an inward inclination toward the nozzle tip, and then extend approximately parallel to the axial direction and connect to the radially outer edge of the second gas outlet 10.

In a cross section along the axial direction, it is preferable that the flow path width of the tip inclined portion 11 of the second outer periphery flow path 9 is wider than the flow path width of the tip straight portion 8 of the first outer periphery flow path 6. The flow path width of the tip inclined portion 11 means the width of the second outer periphery flow path 9 in a direction perpendicular to the extension direction of the tip inclined portion 11 in a cross section along the axial direction, and the flow path width of the tip straight portion 8 means the width of the first outer periphery flow path 6 in a direction perpendicular to the extension direction of the tip straight portion 8 in a cross section along the axial direction. If the tip inclined portion 11 and the tip straight portion 8 are formed in this way, it becomes easier to stably eject the gas-liquid mixture fluid from the tip of the nozzle 1.

The second outer peripheral flow passage 9 is preferably formed at the tip 2 of the nozzle 1 approximately evenly in the circumferential direction around the axial direction, i.e., axially symmetrically. By forming the second outer peripheral flow passage 9 in this way, gas is more easily ejected from the second gas outlet 10 over the entire circumferential direction, and foreign matter such as dust and dirt is less likely to adhere to the tip of the nozzle 1.

The gas pressure at the first gas outlet 7 is preferably higher than the gas pressure at the second gas outlet 10. By ejecting gas from the first gas outlet 7 and the second gas outlet 10 in this manner, the flow of the gas-liquid mixture fluid ejected from the liquid outlet 4 and the first gas outlet 7 is less likely to be impeded by the gas ejected from the second gas outlet 10, making it easier to eject the gas-liquid mixture fluid suitably from the nozzle 1. From the same perspective, it is preferable that the flow rate of the gas ejected from the first gas outlet 7 is higher than the flow rate of the gas ejected from the second gas outlet 10.

As shown in Figures 3, 4, 6, and 7, it is preferable that the upstream side of the second outer peripheral flow passage 9 is connected to the first outer peripheral flow passage 6. By configuring the nozzle 1 in this manner, the nozzle 1 can be made smaller. In addition, the gas supply means provided on the base end side of the first outer peripheral flow passage 6 also serves as the gas supply means provided on the base end side of the second outer peripheral flow passage 9, and the peripheral devices of the nozzle 1 can be simplified. In this case, the gas supplied to the first outer peripheral flow passage 6 passes through the first outer peripheral flow passage 6 and is ejected from the first gas outlet 7, and the gas supplied to the first outer peripheral flow passage 6 is supplied to the second outer peripheral flow passage 9 and is ejected from the second gas outlet 10 through the second outer peripheral flow passage 9.

It is preferable that the upstream side of the second outer peripheral flow passage 9 is connected to the first outer peripheral flow passage 6 via the orifice 14 (see Figures 4, 6, and 7). The orifice 14 is formed as a small flow passage having a smaller flow passage area than the first outer peripheral flow passage 6 on the upstream side and the second outer peripheral flow passage 9 on the downstream side. By connecting the upstream side of the second outer peripheral flow passage 9 to the first outer peripheral flow passage 6 via the orifice 14, the gas supplied to the first outer peripheral flow passage 6 is ejected from the first gas outlet 7 through the first outer peripheral flow passage 6, and is supplied to the second outer peripheral flow passage 9 through the orifice 14 and ejected from the second gas outlet 10 through the second outer peripheral flow passage 9. This makes it easy to make the pressure of the gas at the second gas outlet 10 lower than the pressure of the gas at the first gas outlet 7. Alternatively, it is easy to make the flow rate of the gas ejected from the second gas outlet 10 lower than the flow rate of the gas ejected from the first gas outlet 7. The orifice 14 is preferably provided to connect the upstream portion of the straight tip portion 8 of the first outer peripheral flow passage 6 with the upstream portion of the inclined tip portion 11 of the second outer peripheral flow passage 9.

It is preferable that multiple orifices 14 are provided in the circumferential direction in the axial cross section, and more preferably multiple orifices 14 are provided at approximately equal intervals in the circumferential direction. The number of orifices 14 is, for example, preferably 2 to 12, more preferably 2 to 8, and even more preferably 3 to 6.

The second outer periphery flow passage 9 preferably has a ring-shaped throttle section 12 centered in the axial direction between the tip inclined section 11 and the orifice 14, the throttle section 12 having a narrower flow passage width than the tip inclined section 11. By providing the second outer periphery flow passage 9 with the ring-shaped throttle section 12 in this way, the gas supplied to the second outer periphery flow passage 9 through the orifice 14 is more likely to be distributed approximately evenly in the circumferential direction, making it easier to eject the gas from the second gas outlet 10 over the entire circumferential direction.

The second outer peripheral flow passage 9 preferably has an annular buffer space 13 between the constriction portion 12 and the orifice 14, the buffer space 13 being centered in the axial direction and having a flow passage width wider than that of the constriction portion 12. The orifice 14 is preferably connected to the buffer space 13 of the second outer peripheral flow passage 9. By providing the buffer space 13 in this manner, the gas supplied to the second outer peripheral flow passage 9 through the orifice 14 is more likely to be distributed approximately evenly in the circumferential direction.

The second outer peripheral flow passage 9 is preferably formed downstream of the orifice 14 so as to be approximately evenly spaced in the circumferential direction around the axial direction, i.e., axially symmetrical. By forming the second outer peripheral flow passage 9 in this manner, gas is more easily ejected approximately evenly in the circumferential direction from the second gas outlet 10, and foreign matter such as dust and dirt is less likely to adhere to the tip of the nozzle 1.

The surface of the nozzle 1 at the tip side may be formed flat, but it is preferable that the nozzle 1 has a recessed portion 15 on the surface at the tip side, and the second gas outlet 10 is formed in the recessed portion 15. By forming the recessed portion 15 on the surface at the tip side of the nozzle 1, foreign matter such as dust and powder is less likely to adhere to the tip of the nozzle 1 even when liquid is not being sprayed.

It is preferable that the outer edge of the recess 15 is inclined radially inward toward the base end side of the nozzle 1 in a cross section along the axial direction. It is preferable that the depth of the recess 15 is formed shorter than the radial length of the recess 15. For example, the depth of the recess 15 is preferably 1/20 or more of the radial length of the recess 15, more preferably 1/15 or more, and preferably 1/3 or less, and more preferably 1/5 or less.

The nozzle 1 can be made of metal or resin. Examples of metals include iron, iron alloys (carbon steel, stainless steel, chromium molybdenum steel, manganese molybdenum steel, etc.), copper, copper alloys (brass, etc.), aluminum alloys (duralumin, etc.), nickel alloys (Hastelloy, Monel, etc.), etc. Examples of resins include polyolefin resin, polyester resin, AS resin, ABS resin, acrylic resin, methacrylic resin, polycarbonate resin, polyamide resin, polyacetal resin, phenol resin, melamine resin, urea resin, epoxy resin, fluorine-based resin, unsaturated polyester resin, polyvinyl chloride, polystyrene, etc.

The tip surface of the nozzle 1 is preferably made of a fluororesin. When a recess 15 is formed on the tip surface of the nozzle 1, the tip surface of the nozzle 1 including the recess 15 is preferably made of a fluororesin. This makes it possible to prevent foreign matter such as dust and particles from adhering to the tip surface of the nozzle 1. Examples of fluororesins include polytetrafluoroethylene, ethylene tetrafluoroethylene, and fluorinated ethylene propylene.

The average particle diameter of the liquid sprayed from the nozzle 1 is preferably, for example, 50 μm or less, more preferably 30 μm or less, and even more preferably 10 μm or less. The lower limit of the average particle diameter of the sprayed liquid is not particularly limited, and may be 1 μm or more, 3 μm or more, or 5 μm or more. The liquid may be sprayed as a dry fog, that is, sprayed in a fine mist that does not feel wet to the touch. By spraying the liquid as a dry fog with an average particle diameter of, for example, 10 μm or less, the liquid can be spread evenly throughout the target space in a short time without wetting the target space. The average particle diameter described here means the Sauter mean particle diameter when the particle diameter distribution of the droplets of the liquid sprayed from the nozzle 1 is measured at a point 30 cm away from the tip of the nozzle 1 using a laser diffraction particle size distribution measuring device.

The present invention can also provide a spraying method using the nozzle of the present invention, in which a liquid is ejected from a liquid outlet, a gas is ejected from a first gas outlet, and a gas is ejected from a second gas outlet. It is preferable that the liquid ejected from the liquid outlet and the gas ejected from the first gas outlet are ejected from the tip of the nozzle as a gas-liquid mixed fluid, and it is preferable that the gas ejected from the second gas outlet is ejected so as to surround the gas-liquid mixed fluid from the liquid outlet and the first gas outlet.

The nozzle of the present invention can be used for various purposes such as humidification, cooling, antistatic, air purification, sterilization and cleaning, and infection prevention. The space to be sprayed may be outdoors, an indoor space surrounded by walls and a roof, or a semi-indoor space without a roof or walls and allowing free flow of outside air. Indoor spaces to be sprayed include factories, clean rooms, warehouses, halls, offices, factories, hospitals, nursing homes, stores, schools, homes, livestock sheds, vinyl greenhouses, plant factories, mushroom cultivation rooms, etc. It can also be used for exhaust gas cooling and removing air pollutants from exhaust gases, such as exhaust gas denitrification.

1: nozzle 2: tip 3: central flow passage 4: liquid outlet 5: small diameter tip section 6: first outer peripheral flow passage 7: first gas outlet 8: straight tip section 9: second outer peripheral flow passage 10: second gas outlet 11: inclined tip section 12: constricted section 13: buffer space 14: orifice 15: recessed section 21: inner tube 22: middle tube 23: outer tube

Claims (10)

A nozzle having an axial direction and a radial direction extending from a base end side to a tip end side, and ejecting a gas-liquid mixture fluid from the tip end side,
a tip portion of the nozzle has a central flow passage having a liquid outlet at its tip, a first outer peripheral flow passage formed around the central flow passage and having a first gas outlet at its tip, and a second outer peripheral flow passage formed around the first outer peripheral flow passage and having a second gas outlet at its tip,
When viewed from a nozzle tip side, the liquid outlet is located radially inward from the first gas outlet, and the first gas outlet is located radially inward from the second gas outlet,
The nozzle according to claim 1, wherein the second outer peripheral flow passage has a tip inclined portion that is inclined radially inward toward the tip of the nozzle. The nozzle according to claim 1, wherein the radially outer edge of the second gas outlet is located closer to the nozzle tip than the radially outer edge of the first gas outlet. The nozzle according to claim 2, wherein the outer edge of the liquid outlet is not located closer to the nozzle tip than the radially outer outer edge of the second gas outlet. The nozzle according to claim 1, wherein the first outer circumferential flow passage has a straight tip portion extending from the first gas outlet toward the base end, and the straight tip portion is formed so that the radially outer surface of the first outer circumferential flow passage extends approximately parallel to the axial direction. The nozzle according to claim 4, wherein the flow path width of the tip inclined portion is wider than the flow path width of the tip straight portion in a cross section along the axial direction. The nozzle according to claim 1, wherein the first outer peripheral flow passage is partially blocked when viewed from the nozzle tip side. The nozzle according to claim 1, wherein the nozzle has a recessed portion on the surface at the tip side, and the second gas outlet is formed in the recessed portion. The nozzle of claim 1, wherein the gas pressure at the first gas outlet is higher than the gas pressure at the second gas outlet. an upstream side of the second outer peripheral flow passage communicates with the first outer peripheral flow passage via an orifice;
2. The nozzle according to claim 1, wherein the gas supplied to the first outer circumferential flow passage passes through the first outer circumferential flow passage and is ejected from the first gas outlet, is supplied to the second outer circumferential flow passage through the orifice, and is ejected from the second gas outlet through the second outer circumferential flow passage. The nozzle according to claim 9, wherein the second outer peripheral flow passage has an annular constriction portion centered in the axial direction between the tip inclined portion and the orifice, the flow passage width of which is narrower than that of the tip inclined portion.

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