Spray system

Abstract

To provide a spray system capable of forming mist having high persistence.SOLUTION: (a) in one nozzle, a proportion of particles having a particle size of 1.0 μm or more and less than 7.0 μm is 30% or more and 50% or less in a number-based particle size distribution in a particle size range of 1.0 μm to 60.0 μm at a point 3m ahead of an ejection port of the nozzle, A proportion of particles having a particle size of 1.0 μm or more and less than 15.0 μm is 80% or more and 100% or less, (b) in one nozzle, the number of particles having a particle size of 1.0 μm to 60.0 μm at a point of a 3m tip from an ejection port of the nozzle is 1.0 * 108 / sec or more, (c) in one nozzle, a spray range W at a point of a 30cm tip from an ejection port of the nozzle is 10cm or more and 40cm or less, and (d) ejection directions of a plurality of nozzles are substantially parallel to each other, and an installation interval of the plurality of nozzles is narrower than the spray range W.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a spray system that sprays water from a nozzle to generate mist. [Background technology]

[0002] In recent years, water is sprayed from nozzles to generate mist outdoors for decorative purposes. For example, Non-Patent Document 1 introduces an example in which mist-like water is sprayed from nozzles in a Japanese garden to create an atmosphere of being enveloped in a sea of ​​clouds. [Prior art documents] [Patent documents]

[0003] [Non-Patent Document 1] Yomiuri Shimbun, "A Japanese garden with a refreshing mist, like being enveloped in a sea of ​​clouds", [online], July 10, 2022, Internet<https: / / www.yomiuri.co.jp / national / 20220709-OYT1T50204 / > Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, a method of spraying water outdoors, such as spraying mist in urban areas to cool them (mist cooling), has been known. However, when spraying water from a nozzle to generate fog, it is desirable to create a fog that is more opaque and has a longer shelf life than mist cooling. While conventional fog-generating methods can also create a fog that has a more opaque appearance, the fog disappears relatively quickly when the water spray from the nozzle is stopped, leaving room for improvement in terms of its longevity. The present invention was made in light of the above circumstances, and its purpose is to provide a spray system that can create a fog that has a longer shelf life. [Means for solving the problem]

[0005] The spray system of the present invention that can solve the above problems is as follows. [1] A spray system having multiple nozzles for spraying water and meeting the following requirements (a) to (d). (a) In one of the nozzles, the proportion of particles having a particle diameter of 1.0 μm or more and less than 7.0 μm in the number-based particle diameter distribution in the particle diameter range of 1.0 μm to 60.0 μm at a point 3 m away from the nozzle outlet is 30% or more and 50% or less, and the proportion of particles having a particle diameter of 1.0 μm or more and less than 15.0 μm is 80% or more and 100% or less. (b) For one of the nozzles, the number of particles having a particle diameter of 1.0 μm to 60.0 μm at a point 3 m away from the nozzle outlet is 1.0 × 10 8 More than 1000 pieces / second. (c) For one of the nozzles, the spray width W at a point 30 cm from the nozzle outlet is 10 cm or more and 40 cm or less. (d) The spray directions of the plurality of nozzles are approximately parallel, and the installation interval between the plurality of nozzles is narrower than the spray width W. [2] In the requirement (d), the installation interval between the plurality of nozzles is 0.2 times or more and 0.8 times or less the spray width W. [3] The spray system according to [1], wherein the nozzle is a single-fluid nozzle. [Effects of the Invention]

[0006] According to the spray system of the present invention, even if water is sprayed intermittently from the nozzle, the mist can be maintained for a longer period of time, and a mist with high persistence can be formed. [Brief explanation of the drawings]

[0007] [Figure 1] This shows the particle size distribution based on the number of particles from nozzle A. [Figure 2] This shows the particle size distribution based on the number of particles from nozzle B. [Figure 3] 1 shows a schematic diagram of the nozzle installation form of Installation Examples 1A to 9A shown in Table 3. [Figure 4]1 shows a schematic diagram of the nozzle installation configurations of Installation Examples 1B to 9B shown in Table 3. DETAILED DESCRIPTION OF THE INVENTION

[0008] The spray system of the present invention includes a plurality of nozzles for spraying water and satisfies the following requirements (a) to (d). (a) In one of the nozzles, the proportion of particles having a particle diameter of 1.0 μm or more and less than 7.0 μm in the number-based particle diameter distribution in the particle diameter range of 1.0 μm to 60.0 μm at a point 3 m away from the nozzle outlet is 30% or more and 50% or less, and the proportion of particles having a particle diameter of 1.0 μm or more and less than 15.0 μm is 80% or more and 100% or less. (b) For one of the nozzles, the number of particles having a particle diameter of 1.0 μm to 60.0 μm at a point 3 m away from the nozzle outlet is 1.0 × 10 8 More than 1000 pieces / second. (c) For one of the nozzles, the spray width W at a point 30 cm from the nozzle outlet is 10 cm or more and 40 cm or less. (d) The spray directions of the plurality of nozzles are approximately parallel, and the installation interval between the plurality of nozzles is narrower than the spray width W.

[0009] The spray system of the present invention uses a nozzle that satisfies the above requirements (a) to (c), and installs multiple nozzles so as to satisfy the above requirement (d), thereby spraying water from the nozzles, thereby forming a mist with high persistence. Each requirement is explained in detail below.

[0010] By using a nozzle that satisfies requirements (a) and (b), it is possible to generate a highly opaque mist. To form a highly opaque mist, the water particles sprayed from the nozzle must remain suspended in the air for a certain period of time, and a sufficient number of such water particles must be present in the air. If the water particles sprayed from the nozzle are too large, they will fall quickly, and if they are too small, they will evaporate quickly. Therefore, to form a dense, highly opaque mist, the water particles sprayed from the nozzle must possess the contradictory properties of being resistant to natural settling and evaporating quickly.

[0011] According to requirement (a), the water particles sprayed from the nozzle have a particle size distribution based on the number of particles in the range of 1.0 μm to 60.0 μm (particle size of 1.0 μm or more but less than 60.0 μm), with the proportion of particles with a particle size of 1.0 μm or more but less than 15.0 μm being 80% or more but less than 100%. Water particles with a particle size of less than 15.0 μm are unlikely to settle naturally and quickly after being sprayed from the nozzle. Therefore, by including a large number of water particles with this particle size among the water particles sprayed from the nozzle, a large number of water particles can be suspended in the air. Furthermore, the number of water particles that fall to the ground can be reduced, preventing the ground around the nozzle from becoming wet or muddy.

[0012] According to requirement (a), the water particles sprayed from the nozzle have a particle size distribution based on the number of particles in the range of 1.0 μm to 60.0 μm, with a particle size ratio of 30% to 50% having a particle size of 1.0 μm or more but less than 7.0 μm. In other words, the water particles sprayed from the nozzle include two types: "fine water particles" with a particle size of 7.0 μm to 15.0 μm and "very fine water particles" with a particle size of 1.0 μm to 7.0 μm. Very fine water particles with a particle size of less than 7.0 μm quickly evaporate and disappear after spraying from the nozzle, contributing to increasing the humidity of the sprayed area. Meanwhile, fine water particles with a particle size of 7.0 μm to 15.0 μm evaporate, but are prevented from completely evaporating and disappearing, allowing the fine water particles to remain suspended in the air for a certain period of time. When light hits these fine water particles, the light scatters, creating a cloudy appearance.

[0013] According to requirement (b), a large number of water particles are sprayed from the nozzle, and a large number of water particles are present at a point 3 m away from the nozzle. Combined with requirement (a), this results in the presence of a large amount of fine water particles with a particle diameter of 7.0 μm or more and less than 15.0 μm, and very fine water particles with a particle diameter of 1.0 μm or more and less than 7.0 μm. This allows the formation of a mist with a high degree of cloudiness.

[0014] However, simply satisfying requirements (a) and (b) does not ensure sufficient persistence of the water particles sprayed from the nozzle, and the mist formed by the spray from the nozzle quickly disappears when the spray from the nozzle is stopped. Therefore, in the spray system of the present invention, multiple nozzles are installed to satisfy requirements (c) and (d). By satisfying requirements (c) and (d), the spray ranges of adjacent nozzles overlap, allowing the spray area to maintain a high humidity state for a certain period of time, thereby increasing the persistence of the water particles sprayed from the nozzle. Even when the water spray from the nozzle is stopped, the formed mist can remain for a long time. Therefore, even when water is sprayed intermittently from the nozzle, the mist can be sustained. Furthermore, by spraying in this manner, the generated mist can be made to fluctuate, creating a more natural-looking mist.

[0015] In requirement (a), the proportion of particles having a particle diameter of 1.0 μm or more and less than 15.0 μm may be 83% or more, 85% or more, or 88% or more. The proportion of particles having a particle diameter of 1.0 μm or more and less than 15.0 μm may be higher, for example, 90% or more or 95% or more. On the other hand, since a highly opaque mist can be formed even if the water particles sprayed from the nozzle contain water particles with a somewhat larger particle diameter, the proportion of particles having a particle diameter of 1.0 μm or more and less than 15.0 μm may be 98% or less, 95% or less, or 93% or less. The proportion of particles having a particle diameter of 1.0 μm or more and less than 7.0 μm may be 33% or more, 35% or more, or 48% or less, 45% or less, or 43% or less. Furthermore, according to requirement (a), in the particle size distribution based on the number of particles in the particle size range of 1.0 μm to 60.0 μm, the proportion of particles having a particle size of 7.0 μm or more and less than 15.0 μm is 30% or more and 70% or less, but this proportion may be 35% or more or 40% or more, or may be 65% or less or 60% or less.

[0016] In relation to requirement (a), the proportion of particles with a particle diameter of 1.0 μm or more and less than 9.0 μm in the particle diameter distribution based on the number of particles in the particle diameter range of 1.0 μm to 60.0 μm at a point 3 m away from the nozzle outlet is preferably 40% or more and 80% or less. The proportion of particles with a particle diameter of 1.0 μm or more and less than 9.0 μm may be 45% or more, 50% or more, or 55% or more, or may be 75% or less, 70% or less, or 65% or less.

[0017] In requirement (b), the number of particles with a particle diameter of 1.0 μm to 60.0 μm is 1.5 × 10 8 pcs / sec or more, 2.0×10 8 pcs / sec or more, 2.5×10 8 pieces / second or 3.0 x 10 8 The upper limit of the number of particles having a particle diameter of 1.0 μm to 60.0 μm is not particularly limited, and may be, for example, 1.0 × 10 10 pcs / sec or less, 5.0×10 9 pcs / sec or less, 3.0×10 9 pcs / sec or less, 1.0×10 9 pcs / sec or less, 7.0×10 8 pieces / second or less or 5.0 x 10 8 It may be less than one per second.

[0018] The water particles sprayed from the nozzle may contain water particles with a particle diameter of 60.0 μm or more. To prevent the ground around the nozzle from becoming wet or muddy, it is preferable that the amount of water particles with a particle diameter of 60.0 μm or more be as small as possible. Therefore, the particle ratios of the above-described requirement (a) may be the particle ratios of particles in the particle diameter range of 1.0 μm to 100 μm. Alternatively, in relation to requirement (b), the number of particles with a particle diameter of 60.0 μm or more may be 5% or less, 3% or less, 1% or less, 0.5% or less, or 0.1% or less of the number of particles with a particle diameter of 1.0 μm or more but less than 60.0 μm.

[0019] The particle size distribution according to requirement (a) and the particle count according to requirement (b) are determined using the following duct. A 6-m-long duct made of a transparent plastic plate (e.g., an acrylic plate) is prepared, and a nozzle is installed inside the duct. The duct is formed, for example, with a rectangular cross section, larger than the spray width of the nozzle (e.g., a width of 0.6 to 1.0 m and a height of 1.5 to 2.5 m). A louver is installed in the duct 4 m horizontally from the nozzle outlet, and an air filter (Dearmat (registered trademark) GDM2, manufactured by Japan Air Filter Co., Ltd.) is installed 1 m further ahead of that. The louver consists of multiple vertically extending blades arranged in a row at 50 mm intervals across the width of the duct, and each blade is formed of three blades arranged in a zigzag pattern when viewed from above the duct. Each blade of the blade is 60 mm wide and 1 mm thick, extending from the bottom of the duct to the ceiling. It extends at an angle of +30° or -30° relative to the duct's direction of extension when viewed from above. That is, of the three blades making up the blade, the middle blade extends at a 30° clockwise angle relative to the duct's direction of extension, while the blades on either side of it extend at 30° counterclockwise angles relative to the duct's direction of extension. A 4.5 mm long return is formed at the downstream end of each blade, which extends at a 90° angle relative to the direction of extension of the most downstream blade. Specifically, this return extends at a 90° counterclockwise angle from the downstream end of the most downstream blade. This duct configuration allows the capture of water particles (unevaporated water particles) that remain in the duct between the time the water is sprayed from the nozzle and the time it reaches the filter. These unevaporated water particles can be considered to be water particles sprayed from the nozzle and present 3 m from the nozzle outlet. Hereafter, these unevaporated water particles will be referred to as "undevaporated water particles at a point 3 m from the nozzle outlet." A drain port is provided at the bottom of the duct, between the nozzle and the filter, so that water that accumulates at the bottom of the duct can be discharged from the drain port. The difference between the amount of water supplied to the nozzle, Q1, and the amount drained, Q2, is the amount of evaporated water, and it has been confirmed that this amount of evaporated water matches the amount of evaporated water estimated from the actual measurements of temperature and humidity before and after spraying at a point immediately after the filter.

[0020] The particle size distribution required for requirement (a) is determined as follows: Air is circulated through the duct at a flow rate of 4.0 m / s, and water is sprayed horizontally from the nozzle in the direction of the air flow. A phase Doppler particle analyzer is used to measure the number-based particle size distribution NPD1 at a point 3 m horizontally from the nozzle outlet. An opening is formed on the side of the duct to allow the laser of the phase Doppler particle analyzer to pass through. From the particle size distribution NPD1, the proportion of particles with a diameter of 1.0 μm or greater but less than 7.0 μm and the proportion of particles with a diameter of 1.0 μm or greater but less than 15.0 μm are determined within the particle diameter range of 1.0 μm to 60.0 μm. The measurement time for particle size distribution measurement is set so that the total number of water particles is 10,000 or greater.

[0021] The number of particles required for requirement (b) is calculated as follows. The number-based particle size distribution NPD1 measured above is converted to a volume-based particle size distribution VPD1, and the total volume V of all particle sizes in the particle size distribution VPD1 is calculated. Separately, the evaporation rate R (=(Q1-Q2) / Q1) of water when water is sprayed from the nozzle is calculated from the amount of water supplied to the nozzle Q1 and the amount of drain Q2 in the particle size distribution measurement. Furthermore, the amount of unevaporated water particles Q per second at a point 3 m away from the nozzle outlet is calculated based on the formula Q3 x (1-R) ​​from the amount of water supplied to the nozzle per second Q3 and the evaporation rate R in the particle size distribution measurement. The volume-based particle size distribution VPD2, calculated by multiplying the vertical axis of the previously calculated volume-based particle size distribution VPD1 by Q / V, is converted to a number-based particle size distribution NPD2, and the number of particles in the particle size range of 1.0 μm to 60.0 μm is calculated from the particle size distribution NPD2.

[0022] The spray width W required for requirement (c) is determined as follows: The nozzle is installed facing vertically downward, and at least 50 10mm-wide water collectors are installed closely spaced in a straight line below the nozzle. The water collectors are rectangular parallelepipeds with an open top, all of the same height, length, and width. The nozzle is installed so that the nozzle is located 30cm above the top of the water collector. The boundary (side wall) of adjacently lined up water collectors is located directly below the nozzle outlet, and this position is the spray center. Water is sprayed vertically downward from the nozzle, and the spraying from the nozzle stops when one of the lined up water collectors is filled with more than 80% of its full capacity. The spray width W is determined based on the water collector that collects more than 10% of the maximum water capacity of each collector. For example, if the water collectors with a water collection volume of 10% or more of the maximum collection volume that are located furthest from the spray center are the 10th water collector on each side of the spray center, the spray width W will be 20 cm. The spray width W is set in 1 cm increments.

[0023] In requirement (c), the spray width W is preferably 12 cm or more, more preferably 15 cm or more, and preferably 35 cm or less, and more preferably 30 cm or less. It is preferable that the nozzle sprays water in a full cone shape; that is, when water is sprayed vertically downward from the nozzle, the spray shape from the nozzle to the ground is roughly conical or bell-shaped, and it is preferable that the sprayed water particles are present inside this shape. Therefore, in measuring the spray width W, it is preferable that 90% or more of the water collectors within the range of the spray width W collect 10% or more of the maximum water collection volume.

[0024] Regarding requirements (a), (b), and (c), the conditions for spraying water from the nozzle when measuring particle size distribution, particle count, and spray width W should be matched to the conditions for spraying water from the nozzle in the spray system. The water spray conditions basically require setting the water supply pressure to the nozzle to be the same, which also makes it possible to match the amount of water sprayed from the nozzle. The atmospheric conditions for determining requirements (a) to (c) are a temperature of 18 to 20°C, humidity of 57 to 59% RH, and a water temperature of 13 to 15°C.

[0025] In requirement (d), the nozzle spray direction is determined based on the direction in which the nozzle outlet faces, and can be determined from the structure inside the nozzle near the outlet. The nozzle spray direction is determined, for example, as a vector starting from the nozzle outlet. For example, if water is sprayed from the nozzle in a full cone shape, the nozzle spray direction is the direction from the nozzle outlet toward the center of the circle in the cross section of the cone.

[0026] In the spray system, at least two nozzles are installed so that the spray directions are approximately parallel to each other, and three or more nozzles may be installed so that the spray directions are approximately parallel to each other. As a specific example of the spray directions of multiple nozzles being approximately parallel, the angular difference between the spray directions of multiple nozzles is preferably within 30°, more preferably within 20°, even more preferably within 10°, and even more preferably within 5°.

[0027] The nozzles are installed so that their spray directions are approximately parallel to each other, and the spacing between them is narrower than the spray width W of the nozzles. The spacing between the nozzles is determined based on the center-to-center distance between the nozzle outlets. By installing the nozzles in this manner, the spray ranges of adjacent nozzles at least partially overlap, increasing the survivability of water particles sprayed from the nozzles. It is preferable that the spray ranges of adjacent nozzles, determined by the spray width W, at least partially overlap each other.

[0028] The installation interval between the multiple nozzles is preferably 0.8 times or less, more preferably 0.75 times or less, and even more preferably 0.7 times or less, of the spray width W, which can further increase the persistence of the mist. On the other hand, the installation interval between the multiple nozzles is preferably 0.2 times or more, more preferably 0.25 times or more, and even more preferably 0.3 times or more, of the spray width W. This can reduce the number of installed nozzles and the total amount of water used.

[0029] In the spray system, it is preferable that multiple nozzles are installed on one supply pipe. That is, it is preferable that the spray system has a supply pipe through which water flows and multiple nozzles installed on the supply pipe, and that water is supplied from the supply pipe to each nozzle, thereby spraying water from the nozzle. At least some of the multiple nozzles installed on the supply pipe are installed so as to satisfy the above requirement (d).

[0030] In a spray system, the installation intervals of some of the nozzles among the multiple nozzles may be narrower than the spray width W, and the installation intervals of the remaining nozzles may be the same as or wider than the spray width W. For example, it is preferable that the spray system is composed of multiple units, each of which is made up of multiple nozzles, and that within one unit, the multiple nozzles are installed so that their spray directions are approximately parallel and their installation intervals are narrower than the spray width W, and that the multiple units are installed so that the interval between the units is wider than the spray width W. Note that the interval between units means the installation interval between the closest nozzles in adjacent units. The number of nozzles included in one unit is preferably 2 to 5, more preferably 2 to 4, and even more preferably 2 or 3.

[0031] Known nozzles include single-fluid nozzles that spray only liquid and two-fluid nozzles that spray both liquid and gas. However, it is preferable to use a single-fluid nozzle because it can easily form a mist. The type of nozzle is not particularly limited, and known nozzle structures can be adopted, but it is preferable to use a collision nozzle. A collision nozzle is a nozzle that has an outlet at the tip of the nozzle body and atomizes the straight rod stream emitted from the outlet by colliding it with a collision pin provided on an extension of the outlet. Examples of collision nozzles include nozzles disclosed in International Publication No. 2018 / 123922 and U.S. Patent No. 7,320,443.

[0032] The spray pressure of the nozzle may be appropriately set so as to satisfy the above requirements (a) to (c). The spray pressure of the nozzle (the pressure at which water is supplied to the nozzle) is, for example, preferably 3.0 MPa or more, more preferably 4.0 MPa or more, and even more preferably 5.0 MPa or more. The spray pressure of the nozzle may be 6.0 MPa or more, 8.0 MPa or more, or 10.0 MPa or more. There are no particular restrictions on the upper limit of the spray pressure of the nozzle, but taking into consideration the pressure resistance of the nozzle, it is preferably 25.0 MPa or less, and more preferably 20.0 MPa or less. The pressure described here refers to gauge pressure.

[0033] The amount of spray from one nozzle (amount of spray during spraying) is determined depending on the type of nozzle and the water supply pressure to the nozzle, and is not particularly limited, but may be, for example, 3.0 L / hr or more, 4.0 L / hr or more, 5.0 L / hr or more, or 6.0 L / hr or more, or 40.0 L / hr or less, 35.0 L / hr or less, 30.0 L / hr or less, or 25.0 L / hr or less.

[0034] For one nozzle, the light blocking rate at a point 1 m away from the nozzle outlet is preferably 50% or more, more preferably 60% or more, and even more preferably 65% ​​or more, which allows for the formation of a mist with a highly opaque appearance.

[0035] The light blocking rate can be determined from the laser transmittance using a laser diffraction measurement device. When a laser is irradiated onto water particles, some of the irradiated laser light hits the water particles and is diffracted and scattered, and the light blocking rate is measured at the point 1 m horizontally from the nozzle outlet where the intensity of the diffracted and scattered light is strongest. A light receiving unit is placed at the point where the laser light is irradiated, and the transmittance is measured by irradiating the laser light perpendicular to the nozzle's ejection direction and receiving the light at the light receiving unit, and the light blocking rate is calculated using the formula: Light blocking rate (%) = 100 - transmittance (%).

[0036] Next, we will explain the results of a study into the mist formation ability when spraying water using a specific nozzle. Water was sprayed using two types of nozzles, Nozzle A and Nozzle B, and the spray characteristics and mist formation ability of each nozzle alone were confirmed. Nozzle A and Nozzle B are both single-fluid nozzles, with Nozzle A being a pin jet nozzle and Nozzle B being a swirl nozzle.

[0037] A swirl nozzle is a nozzle that includes a nozzle tip having a nozzle outlet at the tip end of a nozzle body, and multiple grooves extending radially from the nozzle outlet formed on the inner surface of the nozzle tip. The grooves formed in the nozzle tip may extend linearly or arcuately from the nozzle outlet. Inside the nozzle body, liquid introduced into the nozzle outlet passes through the grooves in the nozzle tip, is formed into a swirling flow, and is then sprayed as a mist from the nozzle outlet. Examples of swirl nozzles include the nozzles disclosed in Japanese Patent Application Laid-Open Nos. 2008-104929 and 2009-36316.

[0038] Nozzle A and nozzle B were installed in the duct described above. Water was sprayed from nozzle A and nozzle B, and the particle size distribution was measured 3 m from the nozzle outlet. The spray pressure (water supply pressure to the nozzle) for nozzle A and nozzle B was 6.0 MPa, and the spray rate for nozzle A was 7.4 L / hr, while that for nozzle B was 5.2 L / hr. Figure 1 shows the number-based particle size distribution when water was sprayed from nozzle A, and Figure 2 shows the number-based particle size distribution when water was sprayed from nozzle B. Furthermore, using the method described above, the number of particles in the particle diameter range of 1.0 μm to 60.0 μm and the nozzle spray width W were determined. The results are summarized in Table 1, along with the percentages of particles with diameters of 1.0 μm to less than 7.0 μm and 1.0 μm to less than 15.0 μm in the particle size distributions shown in Figures 1 and 2. Nozzle A satisfied requirements (a) to (c), while nozzle B satisfied requirements (b) and (c) but did not satisfy requirement (a).

[0039] [Table 1]

[0040] Table 2 shows the results of mist formation when water was sprayed from nozzle A and nozzle B under the same conditions as above. Table 2 shows the results of mist formation when water was sprayed from a single nozzle A or nozzle B (cases 1 and 4), and when two or more nozzles A or B were installed 100 mm apart so that the spray directions were approximately parallel and water was sprayed (cases 2, 3, and 5). Water was sprayed from the nozzle for 10 seconds, and then the remaining mist was visually confirmed when spraying was stopped, and the remaining time of the mist was measured. In Table 2, cases 2 and 3 meet all of requirements (a) to (d).

[0041] [Table 2]

[0042] Comparing Nozzle A and Nozzle B, Nozzle A had a longer lingering mist than Nozzle B, and was able to form a mist with a more opaque appearance. When water was sprayed from a single nozzle, in Case 4, which used Nozzle B, the mist disappeared immediately when spraying stopped, while in Case 1, which used Nozzle A, the mist lingered for 4 seconds. When multiple Nozzles A were installed at intervals narrower than the spray width W, in Case 2, where two Nozzles A were installed, the mist lingered for 14 seconds, and in Case 3, where three Nozzles A were installed, the mist lingered for 16 seconds. Cases 2 and 3 show that mist can be sustained even when water is sprayed intermittently from Nozzle A.

[0043] Based on the results of Cases 1 and 2 in Table 2, we examined water consumption in two cases: one in which multiple nozzles were installed at equal intervals so that the nozzle spacing D1 was wider than the spray width W, as shown in Figure 3; and one in which multiple nozzles were installed so that two nozzles constitute one unit, the nozzle spacing D2 within the unit was narrower than the spray width W, and the nozzle spacing D1 between units was wider than the spray width W, as shown in Figure 4. The results are shown in Table 3. In Figures 3 and 4, multiple nozzles 12 are installed on one supply pipe 11, and the spray range from each nozzle 12 is indicated by a dotted line. The nozzle spacing D1 in Figure 3 and the nozzle spacing D1 between units in Figure 4 were set to equal the spray width W + 5 cm; that is, the spray spacing S in Figures 3 and 4 was set to 5 cm. The spray width W was set to a range of 10 cm to 40 cm.

[0044] [Table 3]

[0045] In Table 3, in installation example #A (# = 1-9), multiple nozzles are installed at equal intervals as shown in Figure 3. In installation example #B (# = 1-9), multiple units are installed at equal intervals, with two nozzles per unit, as shown in Figure 4. In installation example #B, the nozzle installation distance D2 within a unit was set to 0.25, 0.5, or 0.75 times the spray width W. The total installation length L was set between 150 cm and 225 cm, and installation examples #A and #B with the same number were set to have approximately the same total installation length L. The water volume during spraying (water supply to the nozzle) was 2.0 mL / s per nozzle. The nozzles sprayed water intermittently, with spraying and pausing repeated at predetermined intervals. The pause time was set to the mist lingering time for cases 1 and 2 in Table 2 minus 2 seconds, which is the time during which the mist formed by the spray does not disappear. That is, in installation example #A, the spray was set to alternate between 10 seconds of spraying and a 2-second break, and in installation example #B, the spray was set to alternate between 10 seconds of spraying and a 12-second break.

[0046] As can be seen from the water consumption results in Table 3, when comparing installation example #A and installation example #B, which have the same number, installation example #B reduces water consumption more than installation example #A. Although installation example #B has more nozzles installed than installation example #A, it can take longer pauses in spraying, thereby reducing total water consumption. This allows for more environmentally friendly mist production and prevents the ground around the nozzles from becoming wet or muddy. Note that the two-second pause in installation example #A is unrealistic considering the actual operation of the nozzles and liquid delivery pump, so it is more realistic to spray continuously from the nozzles in installation example #A. Therefore, in this case, installation example #B has a greater effect in reducing water consumption.

[0047] In the spray system of the present invention, the multiple nozzles may be arranged side by side in the horizontal direction, side by side in the vertical direction, or diagonally with respect to the horizontal direction. The spray direction of each nozzle is preferably approximately horizontal or diagonally downward. For example, the spray direction of the nozzle is preferably in the range of 20° above to 60° below the horizontal direction, more preferably in the range of 10° above to 45° below the horizontal direction, and even more preferably in the range of 5° above to 35° below the horizontal direction.

[0048] The nozzle is preferably installed at a height of 120 cm or less from the ground or water surface, more preferably 100 cm or less, and even more preferably 80 cm or less. There is no particular limit to the lower limit of the nozzle installation height, and the nozzle may be installed at a height of 3 cm or more, 5 cm or more, 10 cm or more, 20 cm or more, or 30 cm or more from the ground or water surface.

[0049] The spray system is preferably installed outdoors, and examples of outdoor spaces to be sprayed include parks, amusement parks, gardens, shrines and temples, event venues, and outdoor public facilities. [Explanation of symbols]

[0050] 11: Supply pipe 12: Nozzle L: Total installation length D1, D2: Nozzle installation interval W: Spray width S: Spray interval

Claims

1. A spray system having multiple nozzles for spraying water and satisfying the following requirements (a) to (d). (a) In one of the nozzles, in a particle size distribution based on the number of particles in a particle size range of 1.0 μm to 60.0 μm at a point 3 m away from the nozzle outlet, the proportion of particles having a particle size of 1.0 μm or more and less than 7.0 μm is 30% or more and 50% or less, and the proportion of particles having a particle size of 1.0 μm or more and less than 15.0 μm is 80% or more and 100% or less. (b) In one of the nozzles, the number of particles having a particle diameter of 1.0 μm to 60.0 μm at a point 3 m away from the nozzle outlet is 1.0 × 10 ８ More than one per second. (c) For one of the nozzles, the spray width W at a point 30 cm away from the nozzle outlet is 10 cm or more and 40 cm or less. (d) The spray directions of the plurality of nozzles are approximately parallel, and the installation interval between the plurality of nozzles is narrower than the spray width W.

2. 2. The spray system according to claim 1, wherein, in the requirement (d), the installation interval between the plurality of nozzles is 0.2 times or more and 0.8 times or less the spray width W.

3. The spray system of claim 1 , wherein the nozzle is a single-fluid nozzle.

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