Mist screen generation apparatus

Abstract

This mist screen generation apparatus has: a mist generation means that sprays mist to form a mist layer in a space; and an airflow generation unit that holds and conveys the mist with a generated airflow. The airflow generation unit has: an airflow generation means that generates the airflow; a flow path expansion section disposed on the downstream side of the airflow generation means, the flow path expansion section having, at the uppermost portion thereof, a flow path cross-section rectangular in shape and larger than the flow path cross-section of the airflow generation means, the flow path cross-section of the flow path expansion section gradually increasing in size from the uppermost portion toward the lowermost portion; a flow path constriction section disposed on the downstream side of the flow path expansion section, the flow path constriction section increasing the rate of the airflow; and an air blowout section disposed on the downstream side of the flow path constriction section, the air blowout section having a rectangular cross-section,.

Description

Mist screen generator

[0001] The present disclosure relates to a mist screen generating device that forms a mist screen and generates a mist screen on which an image is displayed using a projection device such as a projector or cinema.

[0002] Mist screen generators such as that disclosed in Patent Document 1 have been proposed. Mist screens are a technology that maintains mist in the form of a screen in the atmosphere by incorporating mist into a planar airflow. Because mist scatters visible light, it is possible to create a mist screen that is tangible and passable by projecting an image onto the mist using a projection device such as a projector or cinema. Therefore, if a large, uniform mist screen could be created, many people could simultaneously experience the spatial effects of the mist screen, enhancing entertainment value through diverse and powerful effects.

[0003] When forming a mist screen, it is known that the size of the screen onto which the image is projected is affected by the diffusion of the airflow and the amount of mist contained in the airflow. By suppressing the diffusion of the planar airflow over a long distance, the vertical disturbance of the projected image is minimized and the mist concentration within the screen is maintained at a high level. This allows the formation of a large, uniform mist screen. However, if the diffusion of the planar airflow is not sufficiently suppressed, the mist contained in the airflow also diffuses in the thickness direction of the surface, resulting in increased disturbance of the projected image and a decrease in the mist concentration within the screen, making it impossible to expand the screen vertically.

[0004] Therefore, in order to create a large, uniform mist screen and enhance the entertainment value of spatial presentation, a mist screen generator is needed that can suppress the diffusion of the planar air current that transports the mist and maintain the mist concentration contained within the screen over long distances.

[0005] In contrast, conventional mist screen generators have been equipped with a rectifying mechanism such as a honeycomb or filter at the airflow outlet to suppress the diffusion of the planar airflow carrying the mist and maintain the mist concentration within the screen (see, for example, Patent Document 1). FIG. 9 shows the conventional mist screen generator described in Patent Document 1. In FIG. 9, the mist screen generator 900 comprises a mist generating section 901 that generates mist, an airflow generating section 902 for transporting the mist, a blower unit 903, and a filter 904 formed of a porous material. In this mist screen generator 900, the mist generated in the mist generating section 901 is contained in the airflow generated in the airflow generating section 902 (airflow 910A). The mist-containing airflow 910A and the mist-free airflow 910B generated by the blower unit 903 pass through the filter 904, are rectified, and are then ejected into the air. By sandwiching both sides of the mist-containing airflow 910A sprayed out in a planar form with the mist-free airflow 910B, it is possible to suppress the mist from diffusing in the thickness direction (left and right direction in FIG. 9).

[0006] Japanese Patent Application Laid-Open No. 2020-56525

[0007] In the conventional configuration, because air is supplied at a right angle to the air outlet, there is a large pressure loss in the flow path from the airflow generating section 902 and the blower unit 903 to the filter 904, and there is also a large pressure loss within the filter 904, which is made of a porous material, making it impossible to ensure the volume and speed of the airflow needed to transport the mist over long distances.When attempting to increase the volume and speed of the airflow in a conventional mist screen generator, possible changes to the device configuration include increasing the number or output of the blowers, or changing the installation position of the blowers or removing the filter 904, which has a rectifying function.

[0008] However, the former method increases the number of blowers and their output, which leads to increased noise, while the latter method cannot suppress the turbulence of the airflow generated by the blowers, resulting in uneven distribution of the blown air velocity and making it impossible to form a uniform mist screen.

[0009] The present disclosure is intended to solve the above-mentioned conventional problems, and has an object to provide a mist screen generating device that can form a mist screen with a uniform distribution of blown flow velocity.

[0010] In order to achieve the above object, a mist screen generator according to one aspect of the present disclosure comprises: mist generating means for spraying mist to form a mist layer in a space; and an airflow generating section for holding and transporting the mist with the generated airflow, the airflow generating section comprising: airflow generating means for generating the airflow; a flow path expansion section downstream of the airflow generating means, the flow path expansion section having at its top a flow path cross section that is larger than the flow path cross section of the airflow generating means and is rectangular in shape, and the flow path cross section gradually increases from the top to the bottom; a flow path narrowing section downstream of the flow path widening section for accelerating the flow velocity of the airflow; and an air blowing section downstream of the flow path narrowing section having a rectangular cross section.

[0011] As described above, the mist screen generator of the above aspect of the present disclosure diffuses turbulent airflow that has entered the airflow passage along the cross section of the enlarged flow passage, uniforming the flow velocity distribution within the cross section of the flow passage. This makes it possible to generate an airflow with little turbulence and low pressure loss within the flow passage, and to form a mist screen with a uniform distribution of outlet flow velocity.

[0012] FIG. 2C is a front cross-sectional view taken along line B-B in FIG. 2A, showing the overall configuration of the mist screen generator according to the first embodiment of the present disclosure; 6C is a front cross-sectional view taken along line B-B of FIG. 6B , showing the overall configuration of the mist screen generator according to embodiment 3 of the present disclosure.A graph comparing the blowout flow speeds of the mist screen generators according to the second and third embodiments. A perspective view showing the overall configuration of the mist screen generator according to the fourth embodiment of the present disclosure. A front view showing the overall configuration of the mist screen generator according to the fourth embodiment of the present disclosure. A side view showing the overall configuration of the mist screen generator according to the fourth embodiment of the present disclosure. A cross-sectional view showing the overall configuration of the mist screen generator described in Patent Document 1.

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0014] 1 shows the overall configuration of a mist screen generator 1 according to a first embodiment of the present disclosure, which uses mist M as a screen for spatial presentation. In Fig. 1, the mist screen generator 1 blows out airflow generated by a blower unit 2 from an air outlet 3, includes mist M generated by a mist outlet 4 in the blown airflow A, and projects an image onto the mist M from a projection device 5, thereby realizing spatial presentation for an audience 6 using the mist M as a screen.

[0015] The mist screen generator 1 is positioned to blow air toward the floor so that the audience 6 can view the image directly in front of it. Projection of an image from the projection device 5 onto the mist screen can be performed from either the same side as the audience 6 or the opposite side through the mist screen. However, because the projected light L transmits more light than the mist M and reflects less, the clarity of the image decreases when projected from the same side as the audience 6. Therefore, the projection device 5 is positioned to project the image from the opposite side of the mist M from the audience 6. This mist M is contained in the horizontally elongated airflow A blown out from the mist screen generator 1 and is carried far away by the flow of the airflow A. Because the mist M is continuously sprayed from the mist blowout section 4, the mist M is continuously carried by the horizontally elongated airflow A, forming a planar mist M in the space as a mist screen S. By projecting an image using the projection device 5 according to the density and size of the mist M, spatial effects can be realized using the mist M as a screen for the audience 6.

[0016] (Device Configuration) The device configuration of the mist screen generator 1 will be described with reference to Figures 2A to 2E. Figures 2A to 2E are a perspective view (Figure 2A), a front view (Figure 2B), a side view (Figure 2C), a side cross-sectional view (Figure 2D), and a front cross-sectional view (Figure 2E) showing the overall configuration of the mist screen generator according to the first embodiment of the present disclosure.

[0017] The mist screen generator 1 forms the generated mist M into a screen shape, and has a mist blowing section 4 as an example of a mist generating means that sprays the mist M to form a mist layer in space, and an airflow generating section 10 that holds and transports the mist M with the generated airflow A.

[0018] The airflow generating section 10 includes a blower unit 2 as an example of airflow generating means for generating an airflow A, an enlarged flow path section 22 , a flow path narrowing section 23 , and an air blowing section 3 .

[0019] The enlarged flow path section 22 has a rectangular flow path cross section at its top downstream of the blower unit 2 that is larger than the flow path cross section of the blower unit 2, and the flow path cross section gradually becomes larger from the top to the bottom.

[0020] The flow path narrowing section 23 accelerates the flow velocity downstream of the flow path enlargement section 22 .

[0021] The air blowing section 3 has a rectangular cross section downstream of the flow path restrictor 23 .

[0022] More specifically, this mist screen generating device 1 comprises a blower unit 2 arranged in the upper center of the main body housing 21, a flow path expansion section 22 arranged in the interior center of the main body housing 21, a flow path narrowing section 23 arranged in the lower center of the main body housing 21, a straight pipe outlet section 24 arranged in the lower center of the flow path narrowing section 23, and a mist outlet section mounting section 25 externally provided on one side of the straight pipe outlet section 24.

[0023] The air blower unit 2 of the mist screen generator 1 is covered at the top with a rectangular air blower unit cover 26 that connects it to the main body housing 21. The air blower unit 2 may be, for example, an axial fan, a diagonal flow fan, or a centrifugal fan driven by a motor, as long as it takes in air from the atmosphere and supplies it into the main body housing 21, but is not limited to these.

[0024] The expanded flow path section 22 in the main body housing 21 is a tubular member that diverges downward, with its upper portion connected to the blower unit 2 and its lower portion connected to the flow path restrictor 23. The cross section of the expanded flow path section 22 (the x-y plane when the z-axis in FIG. 2A is the vertical direction) through which the airflow flows downward in FIG. 2E is a rectangular shape that gradually increases in size as it extends downward. The cross section of the uppermost portion (i.e., the portion connected to the blower unit 2) (the x-y plane in FIG. 2A) is larger than the cross section of the flow path within the blower unit 2, and the ridge line L1 of the cross section of the flow path at the top of the expanded flow path section 22 is longer than the ridge line L2 of the cross section of the flow path within the blower unit 2. While the expansion angle θ1 in FIG. 2E is 75 degrees, it is preferable that the expansion angle θ1 be greater than or equal to 30 degrees and less than 90 degrees. The expansion angle θ1 is the inclination angle of the inner wall of the expanded flow path section 22 relative to the plane of the cross section of the flow path at the top of the expanded flow path section 22 (the x-y plane in FIG. 2A). When the flow path expansion angle θ1 is 30 degrees or more, the airflow generated by the blower unit 2 may sufficiently expand within the expanded flow path portion 22. When the flow path expansion angle θ1 is less than 90 degrees, the flow path cross section of the expanded flow path portion 22 (the xy plane in FIG. 2A) expands downward in FIG. 2E, so that the airflow generated by the blower unit 2 may sufficiently expand within the expanded flow path portion 22. As an example, the height H1 of the expanded flow path portion 22 in FIG. 2E is three times the flow path cross-sectional ridge line L1 at the top of the expanded flow path portion 22 (H1 = 3L1), but this is not limited thereto as long as the turbulent airflow entering the expanded flow path portion 22 is diffused along the flow path cross section and the flow velocity distribution within the flow path cross section becomes uniform.

[0025] The flow path restrictor 23 is a cylindrical member tapered downward, with its uppermost portion connected to the lowermost portion of the expanded flow path portion 22 and its lower portion connected to the outlet straight pipe portion 24. The flow path cross section of the flow path restrictor 23 is rectangular, with the upper flow path cross section of the flow path restrictor 23 being equal to the lower flow path cross section of the expanded flow path portion 22, and the lower flow path cross section of the flow path restrictor 23 being equal to the flow path cross section of the air blowing section 3. While the flow path restrictor angle θ2 in FIG. 2C is 60 degrees, it is preferable that the flow path restrictor angle θ2 be equal to or greater than 30 degrees and less than 90 degrees. The flow path expanding angle θ2 is the inclination angle of the inner flow path wall of the flow path restrictor 23 with respect to the plane of the flow path cross section at the lowermost portion of the expanded flow path portion 22 (the x-y plane in FIG. 2A). When the flow path restrictor angle θ2 is 30 degrees or greater, it is possible to generate an outlet airflow that can transport mist far away by reducing airflow turbulence within the flow path restrictor 23 and reducing pressure loss within the flow path. When the flow path narrowing angle θ2 is less than 90 degrees, the flow path cross section (xy plane in Figure 2A) of the flow path narrowing section 23 shrinks downward in Figure 2D, so the flow rate can be increased and an outlet airflow can be generated that transports the mist over long distances.

[0026] The air blowing section 3 is a tubular member, the top of which is connected to the bottom of the flow path restricting section 23. The cross section of the air blowing section 3 (xy plane in FIG. 2A ) is rectangular, and includes a straight air outlet section 24 extending from the top to the bottom and an air outlet 27 at the bottom of the bottom. The straight air outlet length H of the straight air outlet section 24 in FIG. 2D is twice the width D of the air outlet 27 (H = 2D), but the straight air outlet length H is preferably equal to or greater than the width D and equal to or less than 40D (D≦H≦40D). The straight air outlet length H is the length of the straight air outlet section 24 extending from the top to the bottom of the air blowing section 3. If the straight air outlet length H is equal to or greater than the width D of the air outlet (H < D), it may be possible to rectify the airflow that has been throttled and accelerated by the flow path restricting section 23. Furthermore, if the outlet straight pipe length H is 40 times the outlet width D (H = 40D), the airflow can be rectified regardless of the flow speed of the airflow passing through the outlet straight pipe section 24, so the required outlet straight pipe length H is 40 times or less the outlet width D. If the outlet straight pipe length H is 40 times or less the outlet width D (H = 40D), the device size can be reduced while still achieving the airflow rectification effect.

[0027] The mist blowing section 4 is an example of a mist generating section or mist blowing section of a mist generating means provided on a mist blowing section mounting section 25 externally provided on one side of the outlet straight pipe section 24. The mist generating section may be an ultrasonic element, a one-fluid nozzle, a two-fluid nozzle, or the like, but is not limited to these.

[0028] (Explanation of Operation) The operation based on the configuration of the present embodiment 1 will be described. When forming the mist screen S in the mist screen generator 1, mist M is discharged at a constant flow rate from the mist blowout section 4. The discharged mist M is carried by the air current A blown out from the outlet 27 and maintained in the downward direction in the form of a screen in the space as shown in Figures 1 and 2A.

[0029] On the other hand, to generate airflow A in the mist screen generator 1, the blower unit 2 is driven to supply a large amount of air into the main body housing 21. The supplied air is diffused by the enlarged flow path section 22 provided in the main body housing 21 so that the flow velocity distribution within the flow path cross section (the x-y plane in FIG. 2A ) becomes uniform, and reaches the flow path narrowing section 23. The flow velocity within the flow path is accelerated by the flow outlet straight pipe section 24 of the air blowing section 3, and the air is then ejected downward from the air outlet 27. The blowing flow velocity and blowing volume are adjusted by controlling the drive of the blower unit 2.

[0030] (Effect) FIG. 3 is a graph comparing the blowing flow velocity between the device configuration of the prior art example shown in FIG. 9 and the mist screen generator 1 of embodiment 1. The measurement point was 10 mm away from the air outlet, at the center position of the air outlet width D (on the center line in FIG. 2C ). The vertical axis represents the blowing flow velocity Uz (m / s), and the horizontal axis represents the measurement position in the longitudinal direction of the mist screen generator 1 (the left-right direction in FIG. 2B ), with the left end of the air outlet 27 in FIG. 2B represented as 0 and the right end as 1. Graph (A) shows the device configuration of the prior art example, and graph (B) shows the mist screen generator 1 of embodiment 1. The type and drive output of the blower fan were the same. As shown in FIG. 3 , the mist screen generator 1 has smaller pressure loss in the flow path than the configuration of the prior art example, resulting in a larger operating air volume of the fan and a nearly doubled blowing flow velocity Uz. Furthermore, compared to the configuration of the prior art, the mist screen generator 1 suppresses flow turbulence within the flow path, thereby reducing the flow velocity distribution in the horizontal axis direction (the ratio between the maximum and minimum points of flow velocity Uz) and the variation in flow velocity at each measurement point (the size of the scale bar indicating the error range).

[0031] As described above, with the mist screen generator 1 of the first embodiment, turbulent airflow that has entered the system is diffused along the cross section of the enlarged flow path 22, uniforming the flow velocity distribution within the cross section of the system. This makes it possible to generate an airflow with minimal turbulence and low pressure loss within the flow path, enabling the formation of a large, uniform mist screen S, for example, 3 m or more in height.

[0032] Second Embodiment FIGS. 4A to 4C are a side view (FIG. 4A), a front cross-sectional view (FIG. 4B), and a plan cross-sectional view (FIG. 4C) showing the overall configuration of a mist screen generator 100 according to a second embodiment of the present disclosure.

[0033] The airflow generated by the blower unit 02 is turbulent at the step at the connection between the lower part of the blower unit 2 and the upper part of the expanded flow path section 22, or at the corners within the expanded flow path section 22, generating vortices. The vortices generated in the expanded flow path section 22 grow within the flow path throttle section 23 and the air blowing section 03, causing the airflow to diffuse after being blown out. In the mist screen generator 1 described in the first embodiment, corner filling members 30 are provided to fill the four corners of the expanded flow path section 22 and the step at the connection between the lower part of the blower unit 2 and the upper part of the expanded flow path section 22, thereby creating a smooth surface, thereby functioning as an airflow turbulence suppression member that suppresses the turbulence of the airflow and the generation of vortices within the expanded flow path section 22. For example, as shown in FIG. 4C , the corner filling members 30 eliminate the corners by covering the four corners of the flow path cross section with a member having a rounded surface R1 (in other words, a curved surface). The corner filling member 30 may be a cut or molded part of resin or metal, putty, urethane, or other material, but is not limited to these.

[0034] FIG. 5 is a graph comparing the blowout flow velocity of the mist screen generator 1 according to the first embodiment and the mist screen generator 100 according to the second embodiment. Graph (A) shows the device configuration of the prior art example shown in FIG. 9 , graph (B) shows the mist screen generator 1 according to the first embodiment, and graph (C) shows the mist screen generator 100 according to the second embodiment. The types and drive power of the blower fans are the same. As shown in FIG. 5 , compared to the device according to the first embodiment, the mist screen generator 100 better suppresses turbulence and vortex generation in the airflow path, resulting in smaller pressure loss and a larger operating airflow rate for the fan, resulting in a higher blowout flow velocity Uz. Furthermore, because the mist screen generator 100 better suppresses flow turbulence in the flow path, the flow velocity distribution in the horizontal axis direction (the ratio between the maximum and minimum points of the flow velocity Uz) and the variation in flow velocity at each measurement point (the size of the scale bar indicating the error range) are smaller.

[0035] According to this configuration, by providing the corner filling member 30, it is possible to generate an airflow with less pressure loss within the flow path and less turbulence, making it possible to more reliably form a large, uniform mist screen.

[0036] (Embodiment 3) Figures 6A to 6G are a perspective view (Figure 6A), a front view (Figure 6B), a side view (Figure 6C), a side cross-sectional view (Figure 6D), a front cross-sectional view (Figure 6E), a plan cross-sectional view (Figure 6F), and a swirler plan view (Figure 6G) showing the overall configuration of a mist screen generator 200 according to embodiment 3 of the present disclosure.

[0037] In this third embodiment, the mist screen generator 1 or 100 described in the first or second embodiment is configured with an axial fan or mixed flow fan as the blower unit 2 to anticipate a large air volume despite its compact size. While an axial fan or mixed flow fan can ensure a large air volume, it generates airflow with a swirling component. For this reason, the mist screen generator 200 is provided with a cylindrical pipe 230 and swirling vanes 231 between the blower unit 2 and the enlarged flow path section 22. The cylindrical pipe 230 and swirling vanes 231 are expected to attenuate the swirling component of the airflow and align the airflow vector in the blowing direction. 6G, in order to attenuate the swirling component of the airflow, the relationship between the blade curvature R2 of the blades 232 constituting the swirler 231 and the swirler diameter D1 is 0.6≦R2 / D1≦0.8, the relationship between the swirler height H2 and the swirler diameter D1 is 0.5D1≦H2≦0.7D1, and the relationship between the device width Y and the swirler diameter D1 is 1 / 2Y≦D1≦Y. When the swirler diameter D1 is equal to or less than the device width Y (D1≦Y), the flow path cross section (xy plane in FIG. 6A) does not change suddenly at the connection between the blower unit 2 and the cylindrical pipe 230 or at the connection between the cylindrical pipe 230 and the flow path expansion section 222, thereby reducing turbulence of the airflow. Similarly, when the swirl impeller diameter D1 is equal to or greater than half the device width Y (½Y≦D1), the flow path cross section (xy plane in FIG. 6A ) does not change suddenly at the connection between the blower unit 2 and the cylindrical pipe 230 or at the connection between the cylindrical pipe 230 and the enlarged flow path section 222, thereby reducing airflow turbulence. When the relationship between the blade curvature R2 and the swirl impeller diameter D1 is 0.6≦R2 / D1≦0.8, the swirling component of the airflow can be sufficiently attenuated within the swirl impeller 231. When the relationship between the swirl impeller height H2 and the swirl impeller diameter D1 is 0.5D1≦H2, the swirl component of the airflow can be sufficiently attenuated within the swirl impeller 231. When H2≦0.7D1, pressure loss within the flow path is reduced, and the operating airflow of the blower unit 2 can be increased.

[0038] In order to deliver the airflow downward in FIG. 6A while suppressing turbulence generated by blower unit 2, the flow path cross section of cylindrical pipe 230 (xy plane in FIG. 6A ) is larger than the flow path cross section of blower unit 2 and smaller than the flow path cross section at the top of expanded flow path section 222. Swirl vane diameter D1 is larger than flow path cross section ridge L2 of blower unit 2 and smaller than the inner diameter of cylindrical pipe 230, so that swirler vane 231 fits inside cylindrical pipe 230. To fit swirler vane 231 inside cylindrical pipe 230, cylindrical pipe height H1 is higher than swirler vane height H2, and swirler vane 231 is located below, away from, and not adjacent to blower unit 2 inside cylindrical pipe 230. In FIG. 6G , the number of blades 232 of swirler vane 231 is, for example, 12, but is not limited to this number as long as it is between 4 and 36. If the number of blades 232 of the swirler vane 231 is less than four, the swirling component of the airflow generated by the blower unit 2 cannot be sufficiently damped, and if the number exceeds 36, the pressure loss in the flow path increases, reducing the operating air volume of the blower unit 2.

[0039] The mist blowing section 4 is provided on a mist blowing section mounting section 25 externally installed on one side of the outlet straight pipe section 24. The mist generating section is configured with a single-fluid or two-fluid nozzle to increase the amount of mist carried on the airflow sprayed out from the outlet 27. By providing the mist blowing section 4 with a single-fluid or two-fluid nozzle, the sprayed mist M can be carried on the blown airflow A without loss and used to form the mist screen S.

[0040] FIG. 7 is a graph comparing the blowing flow velocity of the mist screen generators according to the device configuration of the prior example and the first, second, and third embodiments. Graph (A) shows the device configuration of the prior example shown in FIG. 9 , graph (B) shows the mist screen generator 1 according to the first embodiment, graph (C) shows the mist screen generator 100 according to the second embodiment, and graph (D) shows the mist screen generator 200 according to the third embodiment. The types and drive power of the blowing fans are the same. As shown in FIG. 7 , compared to the devices of the first and second embodiments, the mist screen generator 200 better suppresses turbulence and vortex generation in the airflow path, resulting in smaller pressure loss and a larger operating airflow rate for the fan, resulting in a greater blowing flow velocity Uz. Furthermore, because the mist screen generator 200 better suppresses flow turbulence in the flow path, the flow velocity distribution in the horizontal axis direction (the ratio between the maximum and minimum points of the flow velocity Uz) and the variation in flow velocity at each measurement point (the size of the scale bar indicating the error range) are smaller.

[0041] As described above, with the mist screen generator 200 of the present disclosure, the cylindrical pipe 230 and swirling vanes 231 attenuate the swirling component of the airflow, aligning the airflow vector in the blowing direction, and further diffusing the air along the flow path cross section of the enlarged flow path section 22, uniforming the flow velocity distribution within the flow path cross section. This makes it possible to generate an airflow with less pressure loss within the flow path and less turbulence, making it possible to more reliably form a large, uniform mist screen.

[0042] 8A to 8C are a perspective view (FIG. 8A), a front view (FIG. 8B), and a side view (FIG. 8C) showing the overall configuration of a mist screen generating unit 300 according to a fourth embodiment of the present disclosure.

[0043] The mist screen generating unit 300 is arranged so that the planar outlet airflow Aa generated from the mist screen generator 301a (one example is the mist screen generator 200, 1, or 100) and the planar outlet airflow Ab generated from the mist screen generator 301b (one example is the mist screen generator 200, 1, or 100 with the mist outlet section 4 omitted) are blown out in parallel. The mist outlet section 320 (corresponding to the mist outlet section 4) is arranged between the mist screen generators 301a and 301b, and the spray direction of the mist M is downward in FIG. 8A (the negative direction of the Z axis), or any spray angle or installation position is acceptable as long as the mist M is sandwiched between the outlet airflows Aa and Ab. In order to increase the height of the mist screen S with the mist M sandwiched between the outlet airflows Aa and Ab, it is necessary to match the flow speed and volume of the outlet airflows Aa and Ab. Therefore, it is desirable to align the heights of the outlet 327a of the mist screen generator 301a and the outlet 327b of the mist screen generator 301b, and to link the drive control of the air blower units 352a and 352b.

[0044] The mist screen generating unit 300 suppresses the diffusion of mist M by sandwiching it between the planar discharge airflows Aa and Ab. That is, the discharge airflows Aa and Ab form a screen-like space, and by confining the mist M within this space, the concentration of mist M contained within the mist screen S can be maintained. As a result, a large, uniform mist screen can be formed. Furthermore, because the discharge airflows Aa and Ab exist between the mist M and the surrounding air, even if the mist screen S is subjected to ambient airflows in the usage environment, such as turbulence caused by an air conditioner or by people moving around, the surface layers of the discharge airflows Aa and Ab absorb the turbulence, making it less susceptible to the effects of airflow in the usage environment.

[0045] It should be noted that any of the various embodiments or modifications described above can be appropriately combined to achieve the effects of each. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features from different embodiments or examples are also possible.

[0046] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0047] (Technology 1) A mist screen generating device comprising: mist generating means that sprays mist to form a mist layer in a space; and an airflow generating unit that holds and transports the mist with the generated airflow, the airflow generating unit comprising: airflow generating means that generates the airflow; a flow path expansion unit downstream of the airflow generating means, the flow path expansion unit having at its top a flow path cross section that is larger than the flow path cross section of the airflow generating means and is rectangular, and the flow path cross section gradually increases from the top to the bottom; a flow path narrowing unit downstream of the flow path widening unit that accelerates the flow speed of the airflow; and an air blowing unit with a rectangular cross section downstream of the flow path narrowing unit.

[0048] (Technology 2) The mist screen generating device according to Technology 1, wherein the enlarged flow path portion includes a corner filling member that fills in a step that occurs at a joint with the airflow generating means and a corner within the enlarged flow path portion.

[0049] (Technology 3) A mist screen generator according to Technology 1 or Technology 2, comprising an axial flow fan or a mixed flow fan as the airflow generating means, a cylindrical pipe and swirling blades in a flow path between the airflow generating means and the flow path expansion section, a cross section of the cylindrical pipe being larger than a flow path cross section of the airflow generating means and smaller than a flow path cross section of the flow path expansion section, and an inner diameter of the cylindrical pipe being larger than a diameter of the swirling blades.

[0050] (Technology 4) The mist screen generator according to any one of Technologies 1 to 3, wherein the mist generating means is provided outside the air blowing section and is a one-fluid nozzle or a two-fluid nozzle.

[0051] (Technology 5) A mist screen generator comprising two of the airflow generating units according to any one of technologies 1 to 4, the two airflow generating units being arranged at a distance from each other so as to generate two layers of airflow, and the mist layer generated from the mist generating means being held between the two layers of airflow.

[0052] These configurations allow the turbulent airflow that enters in a diffused state to flow along the cross section of the enlarged flow path, uniforming the flow velocity distribution within the cross section of the flow path. This reduces pressure loss within the flow path and generates a less turbulent airflow, creating a mist screen with a uniform distribution of outlet flow velocity.

[0053] The mist screen generator according to the above aspect of the present disclosure has a uniform flow velocity distribution within the cross section of the flow path, which allows for the generation of airflow with minimal pressure loss and turbulence, making it possible to form large, uniform mist screens, for example, 3 m or more in height. Therefore, not only can it be used as a screen to create new spatial effects, but it can also be used in air purification equipment that blows air over a surface, such as air conditioners or air curtains, or in air conditioning equipment.

[0054] DESCRIPTION OF SYMBOLS 1 Mist screen generating device 2 Blowing unit 3 Air blowing section 4 Mist blowing section 5 Projection device 6 Audience 10 Airflow generating section 21 Main body housing 22 Flow path enlargement section 23 Flow path narrowing section 24 Straight pipe outlet section 25 Mist blowing section mounting section 26 Blowing unit cover 27 Outlet 30 Corner filling member 100 Mist screen generating device 200 Mist screen generating device 202 Blowing unit 230 Cylindrical pipe 231 Swirl vane 232 Blade 300 Mist screen generating unit 301a Mist screen generating device 301b Mist screen generating device 320 Mist blowing section 327a Outlet 327b Outlet 352a Blowing unit 352b Blowing unit 900 Mist screen generating device 901 Mist generating section 902 Airflow generating section 903 Blower unit 904 Filter 910A, 910B Airflow H1 Cylindrical pipe height H2 Swirler impeller height R1 Roundness R2 Blade curvature D1 Swirler impeller diameter θ1 Flow path expansion angle θ2 Flow path narrowing angle D Air outlet width H Air outlet straight pipe length Y Device width A Discharge airflow Aa Discharge airflow Ab Discharge airflow M Mist L Projected light L1, L2 Flow path cross-sectional ridge line S Mist screen

Claims

1. A mist screen generator comprising: mist generating means for spraying mist to form a mist layer in a space; and an airflow generating section for holding and transporting the mist with the generated airflow, the airflow generating section comprising: airflow generating means for generating the airflow; a flow path expansion section downstream of the airflow generating means, the flow path expansion section having at its top a flow path cross section that is larger than the flow path cross section of the airflow generating means and is rectangular, and the flow path cross section gradually increases from the top to the bottom; a flow path narrowing section downstream of the flow path widening section for accelerating the flow velocity of the airflow; and an air blowing section downstream of the flow path narrowing section having a rectangular cross section.

2. A mist screen generator as described in claim 1, wherein the enlarged flow path section is provided with a corner filling member that fills in any steps that occur at the joint with the airflow generating means and any corners within the enlarged flow path section.

3. A mist screen generator as claimed in claim 1 or claim 2, comprising an axial flow fan or a mixed flow fan as the airflow generating means, a cylindrical pipe and swirling impellers in the flow path between the airflow generating means and the flow path expansion section, the cross section of the cylindrical pipe being larger than the flow path cross section of the airflow generating means and smaller than the flow path cross section of the flow path expansion section, and the inner diameter of the cylindrical pipe being larger than the diameter of the swirling impeller.

4. A mist screen generator according to any one of claims 1 to 2, wherein the mist generating means is provided outside the air blowing section and is a one-fluid nozzle or a two-fluid nozzle.

5. A mist screen generator comprising two of the airflow generating units according to any one of claims 1 and 2, the two airflow generating units being positioned at a distance to create two layers of airflow, and the mist layer generated by the mist generating means being held between the two layers of airflow.

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