Patent Publication Number: US-2022228787-A1

Title: Snow making apparatus

Description:
FIELD OF THE INVENTION 
     The present invention relates to a snow making apparatus. 
     BACKGROUND ART 
     Conventionally, as described in Japanese Patent Application Laid-Open No. H11-237152, there has been known a snow making apparatus that makes artificial snow fall in a room. 
     Japanese Patent Application Laid-Open No. H11-237152 includes: a snow catching body formed of an air-permeable film; a mist generator that generates mist in a room; a cooler and a blower that send low-temperature air into the room; and a striking body that strikes the snow catching body from a back side opposite to an adhering surface to which snow adheres. According to this snow making apparatus, the mist (atomized water droplets) generated by the mist generator is frozen in the low-temperature air, and this frozen body adheres to the adhering surface of the snow catching body. Then, by striking the snow catching body with the striking body from the back side, snow is shaken off from the snow catching body in the room. 
     In the snow making apparatus disclosed in Japanese Patent Application Laid-Open No. H11-237152, a water jetting port in the mist generator faces downward, and the adhering surface of the snow catching body extends along the vertical direction. With such a configuration, it is difficult to make the frozen body efficiently adhere to the adhering surface of the snow catching body. Accordingly, it is difficult to efficiently make the frozen body grow to agglomerated-snowflakes (snow having a large size formed by bonding of fine snowflakes having a fine particle size to each other) on the adhering surface. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a snow making apparatus capable of efficiently making agglomerated-snowflakes (large snowflakes). 
     A snow making apparatus according to an aspect of the present invention includes: a snow making container having an inner space for snow making; a supply unit configured to supply fine snow or fine water droplets to the inner space; a catching unit for catching the fine snow or fine snow formed from the water droplets; and a drive unit configured to move the catching unit toward a place where the fine snow is flying in the inner space. The catching unit is configured to be shaken thereby making snow caught by the catching unit fall off from the catching unit. 
     A snow making apparatus according to another aspect of the present invention includes: a snow making container having an inner space for snow making; a supply unit configured to supply fine snow or fine water droplets to the inner space; a catching unit for catching the fine snow or fine snow formed from the water droplets; a drive unit configured to move the catching unit toward a place where the fine snow is flying in the inner space; and a fall-off unit configured to make snow caught by the catching unit fall off from the catching unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view schematically illustrating a configuration of a snow making apparatus according to a first exemplary embodiment; 
         FIG. 2  is an exploded view schematically illustrating a configuration of the inside of a drum of the snow making apparatus; 
         FIG. 3  is a schematic view for describing a mounting state of a catching unit; 
         FIG. 4  is a schematic view for describing a striking body and a moving mechanism in a snow making apparatus according to a second exemplary embodiment; 
         FIG. 5  is a schematic views for describing a snow making nozzle disposed in a snow making apparatus according to a fifth exemplary embodiment; 
         FIG. 6  is a view schematically illustrating a snow making apparatus according to another exemplary embodiment; and 
         FIG. 7  is a schematic view for describing a mounting state of a catching unit according to another exemplary embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, exemplary embodiments are described in detail with reference to drawings. 
     First Exemplary Embodiment 
     First, a configuration of a snow making apparatus  1  according to a first exemplary embodiment will be described with reference to  FIG. 1  and  FIG. 2 . The snow making apparatus  1  is applied to a snowfall test apparatus having a test chamber  100 . The snow making apparatus  1  is mounted on a ceiling portion of the test chamber  100 , and makes artificial snow S that falls in the test chamber  100 . The artificial snow S includes agglomerated-snowflakes (large snowflakes) formed by bonding of fine snowflakes to each other. The artificial snow S has a size (width) of about 5 to 10 mm, for example. As illustrated in  FIG. 1 , the snow making apparatus  1  includes: a supply unit  10 ; a drum  20  which is a snow making container having an inner space; a blower  30 ; and air conditioner  40 . Further, the snow making apparatus  1  includes a circulation circuit  50  that circulates low-temperature air. In the circulation circuit  50 , the supply unit  10 , the drum  20 , the blower  30  and the air conditioner  40  are arranged in this order. The circulation circuit  50  includes: a feed path  51  for feeding low-temperature air from the air conditioner  40  to the supply unit  10  and the drum  20 ; and a return path  52  for returning air from the drum  20  to the air conditioner  40 . To thermally isolate the circulation circuit  50  from the test chamber  100 , heat insulation is provided to the circulation circuit  50 . 
     The supply unit  10  supplies fine snowflakes to the inner space of the drum  20 . The supply unit  10  in the present exemplary embodiment includes: a snow making nozzle  11  for jetting fine water droplets; and a snow making duct  12  for guiding fine snowflakes formed from the water droplets jetted from the snow making nozzle  11  to the inner space of the drum  20 . 
     The snow making nozzle  11  is disposed outside the snow making duct  12 , and jets atomized water droplets from an inlet of the snow making duct  12  toward the inside of the snow making duct  12 . As the snow making nozzle  11 , a one-fluid nozzle may be used, or a two-fluid nozzle may be used. 
     The snow making duct  12  is disposed downstream of the snow making nozzle  11  in a circulating direction of low-temperature air. The low-temperature air whose temperature is adjusted to a temperature below a freezing point by the air conditioner  40  is introduced into the snow making duct  12 . With such a configuration, the water droplets jetted from the snow making nozzle  11  become fine snowflakes in the snow making duct  12 , and are guided into the drum  20 . In the present exemplified embodiment, as shown in  FIG. 1 , an open space exists between an outlet of the feed path  51  and the inlet of the snow making duct  12 , and the snow making nozzle  11  is disposed in the open space. 
     The snow making apparatus  1  further includes a snow adhesion preventing unit for preventing fine snowflakes from adhering to the inner surface of the snow making duct  12 . The snow adhesion preventing unit includes a blower or a nozzle  14  that feeds air along the inner surface of the snow making duct  12 . The air flows along the inner surface of the snow making duct  12  and hence, it is possible to prevent snow from adhering to the inner surface of the snow making duct  12 . The snow adhesion preventing unit is not an indispensable in the snow making apparatus according to the present invention, and may be omitted. 
     The inner space of the drum  20  functions as a space for snow making. The drum  20  is disposed downstream of the supply unit  10  (snow making duct  12 ) in the circulating direction of the low-temperature air. In the inner space of the drum  20 , agglomerated-snowflakes is made from fine snowflakes supplied from the snow making duct  12 . The detailed configuration of the inside of the drum  20  will be described later. 
     An air blower  30  is disposed in the return path  52 . The blower  30  is used for circulating low-temperature air between the air conditioner  40 , the snow making duct  12 , and the drum  20 . The air conditioner  40  cools the air returned from the drum  20  through the return path  52 , and blows out the cooled low-temperature air to the feed path  51 . The low-temperature air is fed into the snow making duct  12  and the drum  20  through the feed path  51 . 
     Next, the configuration of the inside of the drum  20  will be described in detail with reference to  FIG. 2 .  FIG. 2  illustrates a state where the drum  20  is in a disassembled state. 
     As illustrated in  FIG. 2 , the drum  20  includes: a body portion  22  having a hollow cylindrical shape and opening at both ends; a top plate  21  having a disk shape that closes an upper-side opening of the body portion  22 ; and a bottom plate  23  having a disk shape that closes a lower-side opening of the body portion  22 . A snow outlet  23 A is formed in the bottom plate  23 . The snow outlet  23 A is provided for making agglomerated-snowflakes made in the drum  20  fall toward in the test chamber  100  ( FIG. 1 ). The top plate  21  and the bottom plate  23  are mounted on both end portions of the body portion  22  respectively by fixing jigs such as screws, for example. In  FIG. 2 , for the sake of convenience, the drum  20  is illustrated in a state where the body portion  22  is separated from the top plate  21  and the bottom plate  23 . 
     In the snow making duct  12 , an outflow port  12 A through which the fine snow made in the snow making duct  12  is allowed to flow out is formed. The outflow port  12 A is formed on a side opposite to an inlet side where the snow making nozzle  11  is disposed. As illustrated in  FIG. 2 , a portion of the snow making duct  12  on an outflow port  12 A side penetrates the top plate  21 , and is inserted into an inner space of the drum  20 . With such a configuration, the fine snow and the low-temperature air are supplied to the inner space of the drum  20  from the top plate  21  side. In place of the configuration where the snow making duct  12  penetrates the top plate  21 , the snow making duct  12  may be configured such that an end portion of the snow making duct  12  on an outflow port  12 A side is joined to the top plate  21 . 
     An outlet  21 A for air is formed in the top plate  21 . Air in the drum  20  flows out from the outlet  21 A to the outside of the drum  20  and, thereafter, the air returns to the air conditioner  40  through the return path  52  ( FIG. 1 ). The outlet  21 A may be omitted. In this case, low-temperature air may not be circulated between the air conditioner  40  and the drum  20 . 
     The snow making apparatus  1  further includes: a catching unit  60  for catching fine snow supplied to the inner space of the drum  20  from the snow making duct  12 ; and a drive unit  70  for moving the catching unit  60  toward areas in the inner space where fine snow is flying. 
     In the present exemplary embodiment, the catching unit  60  is formed of a flexible sheet-like member having a quadrangular shape and made of Teflon (registered trademark). In the present exemplary embodiment, a plurality of (four in  FIG. 2 ) catching units  60  are provided. 
     The drive unit  70  includes: a motor  71  mounted on the top plate  21 ; and a rotary shaft  72  connected to the motor  71  and penetrating the center of the top plate  21 . By driving the motor  71 , the rotary shaft  72  rotates about an axis of the rotary shaft  72  at constant speed. A rotational speed of the rotary shaft  72  may be variable. 
     The rotary shaft  72  is disposed in the drum  20  at the center in the radial direction, and supports the plurality of catching unit  60 . Specifically, as illustrated in  FIG. 2 , the plurality of catching units  60  are arranged at an equal interval about the rotary shaft  72 . Each catching unit  60  is mounted on an outer peripheral portion of the rotary shaft  72  in a posture where the catching unit  60  extends radially outwardly from the rotary shaft  72 . In other words, the plurality of catching units  60  are disposed radially about the rotary shaft  72  and are fixed to the rotary shaft  72 . The plurality of catching units  60  rotate about the rotary shaft  72  by driving the motor  71 . With such an operation, the respective catching units  60  move in one direction in the circumferential direction. 
     The snow making duct  12  supplies fine snow toward a region where the rotating catching units  60  pass in the inner space of the drum  20 , that is, a region disposed around the rotary shaft  72 . That is, the outflow port  12 A of the snow making duct  12  opens toward the region where the catching units  60  pass in the inner space of the drum  20 . Accordingly, when the plurality of catching units  60  are driven, the fine snow blown out from the snow making duct  12  is caught by the main surfaces (surfaces facing the rotational direction) of the plurality of catching units  60 . 
     The snow making apparatus  1  further includes: frames  61  (support members) that support the catching units  60 ; and spatula-shaped snow scraping portions attached to the frames  61 . That is, the frame  61  and the snow scraping portion are mounted on each of the plurality of catching units  60 . Each frame  61  is a frame member having an upper side portion, a lower side portion, and outer side portions that connect outer ends of the upper side portions and outer ends of the lower side portion. Each frame  61  surrounds an outer periphery of the catching unit  60 . In the present exemplary embodiment, the catching unit  60  is mounted on the frame  61  at two points, that is at upper and lower points. However, the present invention is not limited to such a configuration. 
     The snow scraping portion is a portion for scraping off snow adhering to the inner surface of the drum  20 . The snow scraping portion includes an upper snow scraping portion  62 , a lower snow scraping portion  63 , and an outer snow scraping portion  64 . When the motor  71  is operated, the upper snow scraping portion  62 , the lower snow scraping portion  63 , and the outer snow scraping portion  64  move around the rotary shaft  72  while being in contact with the inner surface of the drum  20 . These snow scraping portions may be formed of, for example, a sheet made of Teflon (registered trademark), a broom-shaped metal body, or a broom-shaped resin body. The snow scraping portion may be disposed on only one catching unit  60 . 
     The upper snow scraping portion  62  is a portion for scraping off snow adhering to the inner surface of the top plate  21 . The upper snow scraping portion  62  is mounted on an upper side portion of the frame  61  in an extending manner in the radial direction of the drum  20 . The lower snow scraping portion  63  is a portion for scraping off snow adhering to the inner surface of the bottom plate  23 . The lower snow scraping portion  63  is mounted on a lower side portion of the frame  61  in an extending manner in the radial direction of the drum  20 . Further, the lower snow scraping portion  63  conveys the snow fallen on the bottom plate  23  to a snow outlet  23 A. The outer snow scraping portion  64  is a portion for scraping off snow adhering to the inner peripheral surface of the body portion  22 . The outer snow scraping portion  64  is mounted on an outer side portion of the frame  61  in an extending manner in the axial direction of the rotary shaft  72 . 
     In the present exemplary embodiment, each catching unit  60  is formed in a sheet shape and is mounted on the frame  61  in a slackened state.  FIG. 3  schematically illustrates a mounting state of the catching unit  60 . The size of the catching unit  60  in the vertical direction is larger than the size of the frame  61  in the vertical direction, and an upper end portion and a lower end portion of the catching unit  60  are attached to the upper side portion and the lower side portion of the frame  61  respectively. An outer side portion of the catching unit  60  is not attached to the outer side portion of the frame  61 . With such a configuration, the catching unit  60  is in a state where the catching unit  60  expands in a curved shape toward a center portion in the vertical direction from an upper end portion and a lower end portion. The catching unit  60  is shaken when compressed air is blown to the catching unit  60 , for example. 
     The catching unit  60  may have the same size as the frame  61 . Also in this case, for example, at an upper end portion of the catching unit  60 , only a portion of the catching unit  60  on a rotary shaft  72  side is mounted on the frame  61 , and at a lower end portion of the catching unit  60 , only a portion of the catching unit  60  on a side opposite to the rotary shaft  72  is mounted on the frame  61 . With such a configuration, the catching unit  60  can be slackened. 
     In the snow making apparatus  1  according to the present exemplary embodiment, the snow caught by the catching units  60  falls off from the catching units  60  due to shaking of the catching units  60 . Specifically, the snow making apparatus  1  further includes a compressed air supply unit  80  mounted on the top plate  21 . Compressed air is blown from the compressed air supply unit  80  toward the catching unit  60 . With such an operation, the catching units  60  are shaken, and snow falls off from the main surfaces of the catching units  60 . That is, the compressed air supply unit  80  functions as a fall-off unit that causes the snow caught by the catching units  60  to fall off from the catching units  60 . A blow-out port of the compressed air supply unit  80  is positioned above the snow outlet  23 A. 
     Next, the manner of operation of the snow making apparatus  1  will be described. 
     First, a temperature in the inner space of the snow making duct  12  and the temperature in the inner space of the drum  20  are controlled to temperatures below a freezing point by the air conditioner  40 . That is, low-temperature air whose temperature is controlled to a temperature below the freezing point by the air conditioner  40  is supplied to the inner space of the snow making duct  12  and the inner space of the drum  20  through the feed path  51  ( FIG. 1 ). Then, the air that flows out from the outlet  21 A ( FIG. 2 ) of the drum  20  returns to the air conditioner  40  through the return path  52  ( FIG. 1 ). 
     On the other hand, when atomized water droplets are jetted into the snow making duct  12  from the snow making nozzle  11 , the water droplets turned into the fine snow in the low-temperature air. Then, the fine snow is introduced into the inner space of the drum  20  through the snow making duct  12 . 
     In the inner space of the drum  20 , a state is brought about where the fine snow is flying in the entire inner space. When the rotary shaft  72  is rotated about the axis of the rotary shaft  72  by driving the motor  71  in such a state, the catching units  60  move around the rotary shaft  72 . That is, the catching units  60  move toward places where the fine snow is flying. With such an operation, the fine snow flying in the inner space of the drum  20  is efficiently caught by the catching unit  60 , and hence, the fine snow adheres to the main surfaces of the catching units  60 . A part of the fine snow supplied from the snow making duct  12  is directly blown off to the catching units  60 . 
     Then, the fine snow is stacked on the main surface of the catching unit  60  and hence, agglomerated-snowflakes formed of snowflakes having a large size is made. The agglomerated-snowflakes falls off from the catching unit  60  by blowing compressed air to the catching units  60  from the compressed air supply unit  80 . The fallen agglomerated-snowflakes is accumulated on the bottom plate  23  of the drum  20 , and the agglomerated-snowflakes is moved on the bottom plate  23  and is made to fall off through a snow outlet  23 A by the lower snow scraping portion  63 . As descried above, in the test chamber  100  ( FIG. 1 ), it is possible to reproduce a snowfall environment of agglomerated-snowflakes. 
     Second Exemplary Embodiment 
     Next, a snow making apparatus according to a second exemplary embodiment will be described. The second exemplary embodiment basically has substantially the same configuration as the first exemplary embodiment. However, the second exemplary embodiment differs from the first exemplary embodiment with respect to the configuration for shaking catching units  60 . Hereinafter, only points which make the second exemplary embodiment differ from the first exemplary embodiment are described. 
     As illustrated in  FIG. 4 , the snow making apparatus according to the second exemplary embodiment includes a striking body  81  that strikes and shakes the catching unit  60  in place of the compressed air supply unit  80  ( FIG. 2 ). The snow making apparatus further includes a moving mechanism  82  for moving the striking body  81  between a striking position where the striking body  81  strikes the catching unit  60  and a retracted position located away from the catching unit  60 . The striking body  81  and the moving mechanism  82  function as a fall-off unit for making the snow caught by the catching unit  60  fall off from the catching unit  60 . 
     When a certain amount of snow is stacked on the catching unit  60  and agglomerated-snowflakes are made on the catching unit  60 , the striking body  81  moves from the retracted position to the striking position, and impinges on the frame  61 . With such an operation, the catching unit  60  is shaken so that it is possible to make the agglomerated-snowflakes fall off from the catching unit  60 . 
     A vibrating body (not illustrated) that vibrates the catching unit  60  may be used in place of the striking body  81  and the moving mechanism  82 . The vibrating body may be configured to vibrate in a state where the vibrating body is brought into contact with the frame  61 , or the vibrating body may directly vibrate the catching unit  60  in a state where the vibrating body is brought into contact with the catching unit  60 . These components may also be used together with the compressed air supply unit  80 . 
     Third Exemplary Embodiment 
     Next, a snow making apparatus according to a third exemplary embodiment will be described. The third exemplary embodiment is basically substantially equal to the first and second exemplary embodiments. However, the third exemplary embodiment differs from the first and second exemplary embodiments in the manner of shaking the catching unit  60 . Hereinafter, only the points which make the third exemplary embodiment different from the first and second exemplary embodiments are described. 
     In the third exemplary embodiment, agglomerated-snowflakes fall off from the catching unit  60  due to shaking of the catching unit  60  generated by a wind pressure from the snow making duct  12 . Specifically, air supplied from the snow making duct  12  flows in the drum  20  while changing a flow direction into a circumferential direction so that the catching unit  60  is shaken and the agglomerated-snowflakes fall off from the catching unit  60 . That is, the snow making duct  12  blows out an air flow for shaking the catching unit  60  so that the agglomerated-snowflakes fall off. 
     With such an operation, in the same manner as the first and second exemplary embodiments, it is possible to reproduce a snowfall environment where agglomerated-snowflake are made to fall off from the catching unit  60 . In the third exemplary embodiment, the catching unit  60  is shaken using the flow of a circulating air. Accordingly, it is not necessary to provide the compressed air supply unit  80  ( FIG. 2 ) and the striking body  81  and hence, the configuration of the snow making apparatus can be further simplified. 
     Fourth Exemplary Embodiment 
     Next, a snow making apparatus according to a fourth exemplary embodiment will be described. The fourth exemplary embodiment is basically substantially equal to the first exemplary embodiment. However, the forth exemplary embodiment differs from the first exemplary embodiment with respect to a point that snow is made to fall off from the catching unit  60  without shaking the catching unit  60 . Hereinafter, only points which make the fourth exemplary embodiment differ from the first exemplary embodiment are described. 
     In the fourth exemplary embodiment, the catching unit  60  is formed of a member that is not shaken (minimally deformed) by blowing of the compressed air, for example, a metal wire mesh, a porous plate, or the like. The compressed air supply unit  80  functions as a fall-off unit for making snow caught by the catching unit  60  fall off from the catching unit  60 . Specifically, although the catching unit  60  per se is not shaken by compressed air blown from the compressed air supply unit  80 , snow stacked on the catching unit  60  falls off from the catching unit  60  by receiving a force of the compressed air. 
     According to the fourth exemplary embodiment, it is unnecessary to mount the catching unit  60  on the frame  61  such that the catching unit  60  is easily shaken. The forth embodiment is also not limited to a case where a member which is easily shaken, such as a flexible sheet is used as the catching unit  60 . Accordingly, a degree of freedom in forming the catching unit  60  is increased. 
     Fifth Exemplary Embodiment 
     Next, a snow making apparatus according to a fifth exemplary embodiment will be described. The fifth exemplary embodiment is basically substantially equal to the first exemplary embodiment. However, the fifth exemplary embodiment differs from the first exemplary embodiment with respect to a point that the snow making nozzle  11  is disposed in the drum  20 . Hereinafter, only points which make the fifth exemplary embodiment differ from the first exemplary embodiment are described. 
     In this exemplary embodiment, the supply unit  10  includes the snow making nozzles  11  which supply fine water droplets into the inner space of the drum  20 , and do not include the snow making duct  12  ( FIG. 1 ). As illustrated in  FIG. 5 , the snow making nozzles  11  are disposed in a downwardly directed manner in the inner space of the drum  20  in the vicinity of the top plate  21 . More specifically, the snow making nozzles  11  are disposed in the inner space of the drum  20  above the region where the catching units  60  rotate and pass, and supplies fine water droplets toward the region where the catching units  60  pass in a region around the rotary shaft  72 . Only one snow making nozzle  11  may be disposed in the drum  20 , or a plurality of snow making nozzles  11  may be disposed. In the configuration illustrated in  FIG. 5 , the upper snow scraping portion  62  is omitted. 
     In the present exemplary embodiment, a height of the drum  20  is set larger than the height of the drum  20  in the first exemplary embodiment. That is, the height of the drum  20  is larger than a height of the frame  61 . With such a configuration, even in a case where the snow making nozzle  11  is disposed in the drum  20 , a certain distance or more can be secured between the snow making nozzle  11  and the catching unit  60 . 
     A temperature in the inner space of the drum  20  is controlled to below a freezing point by the air conditioner  40  ( FIG. 1 ). Accordingly, in the inner space of the drum  20 , fine snow is formed from water droplets jetted from the snow making nozzle  11 , and the fine snow is caught by the catching units  60  moving around the rotary shaft  72 . Then, in the same manner as the first exemplary embodiment, agglomerated-snowflakes are made on the main surface of the catching unit  60 , and the snow falls off from the catching unit  60  by shaking the catching unit  60 . According to the present exemplary embodiment, the snow making duct  12  can be omitted and hence, the configuration of the snow making apparatus can be further simplified. 
     OTHER EXEMPLARY EMBODIMENTS 
     Other exemplary embodiments of the present invention are described hereinafter. 
     As illustrated in  FIG. 6 , a downstream end of the feed path  51  may be connected to a portion (for example, a duct side peripheral portion) of the snow making duct  12  other than the inlet. In this case, the snow making nozzle  11  may be positioned outside the snow making duct  12  or may be positioned inside the snow making duct  12 . In this case, water droplets are jetted from the snow making nozzle  11  toward air-conditioned air fed from the feed path  51 . A downstream end of the feed path  51  may be connected to the snow making duct  12 , and the snow making nozzle  11  may be positioned in the feed path  51 . 
     The catching unit  60  is not limited to the case where the catching unit  60  is attached to the frame  61  at two upper and lower positions. For example, as illustrated in  FIG. 7 , the catching unit  60  may be attached to the frame  61  at two positions on left and right sides. In this case, the catching unit  60  is fixed to an outer side portion of the frame  61  and the rotary shaft  72 , but is not fixed to the upper side portion and the lower side portion of the frame  61 . 
     A snow quality adjusting nozzle (not illustrated) may be disposed below the snow outlet  23 A so as to enable falling of more wetted artificial snow S in the test chamber  100 . 
     In the first exemplary embodiment, the configuration where the catching unit  60  is shaken by blowing compressed air to the catching unit  60  has been described as one example. The respective exemplary embodiments are not limited to such configuration. For example, it may be possible to make snow fall off from the catching unit  60  by shaking the catching unit  60  with a blower (not illustrated). As another unit for shaking the catching unit  60 , it may be possible to provide a unit that suddenly stops the catching unit  60  that is rotating. In this case, the catching unit  60  is shaken due to a sudden stoppage of the catching unit  60  so that snow falls off from the catching unit  60 . 
     In the first exemplary embodiment, the sheet-like member made of Teflon (registered trademark) is described as an example of the catching unit  60 . However, the invention is not limited to such a case. For example, a sheet-like member made of high density polyethylene, a mesh-like member made of Teflon (registered trademark), a metal plate, a cloth, or the like may be used as the catching unit  60 . The present invention is not limited to the case where a plurality of catching units  60  are disposed, and only one catching unit  60  may be disposed. 
     The drive unit  70  is not limited to the configuration where the catching units  60  are rotated about the rotary shaft  72  only in one direction. For example, the drive unit  70  may not allow the catching units  60  to rotate up to 360° about the rotary shaft  72 , and may change the direction of movement of the catching units  60  in the circumferential direction every time the catching units  60  are rotated by 180° about the rotary shaft  72 , for example. That is, the direction of movement of the catching units  60  may be changed by rotating the rotary shaft  72  in the forward and reverse directions. 
     Further, the drive unit  70  is not limited to the configuration of rotating the catching units  60 , and the drive unit  70  may allow the catching units  60  to perform the translational motion. In this case, the drive unit  70  is configured to linearly move the catching units  60  using a ball screw or the like in place of rotating the rotary shaft  72  by the motor  71 . In such a case, it is preferable that the drum  20  be formed of a polygonal (quadrangular) tube. 
     The outflow port  12 A of the snow making duct  12  may open toward a region other than the region where the catching units  60  pass in the inner space of the drum  20 . 
     The catching unit  60  is not limited to the case where the catching unit  60  is supported by the frame  61  in a slackened state, and the catching unit  60  may be supported by the frame  61  in a stretched state. 
     Some or all of the upper snow scraping portion  62 , the lower snow scraping portion  63 , and the outer snow scraping portion  64  may be omitted. When all of these are omitted, a striking body that strikes the top plate  21  and the body portion  22  of the drum  20  may be provided. A vibrating body that vibrates the top plate  21  and the body portion  22  may be provided. A nozzle that blows compressed air to an inner surface of the top plate  21  and an inner surface of the body portion  22  may be provided. Such a nozzle can make snow fall off from the top plate  21  and the body portion  22 . The striking body is disposed outside or inside the drum  20  and is configured to strike the drum  20 . The vibrating body is arranged to be brought into contact with the drum  20  and is configured to vibrate the drum  20 . All of the snow scraping portions  62 ,  63  and  64 , the striking body, the vibrating body, and the nozzle form snow falling accelerators for making snow adhering to the inner surface of the drum  20  (snow making container) fall off from the inner surface. 
     The catching unit  60  is not limited to the case where the catching unit  60  is attached to the frame  61  in an arcuately curved state as illustrated in  FIG. 3 . The catching unit  60  may be attached in a state where the catching unit  60  is curved in a wave shape, for example. 
     The bottom plate  23  may be omitted. In this case, the drum  20  takes a state where the lower surface of the drum  20  is completely opened. Also in this case, the lower snow scraping portion  63  is also omitted. 
     The snow making nozzle  11  may be disposed in the snow making duct  12 . 
     The size of snow may be adjusted by adjusting a rotational speed of the rotary shaft  72  or a jetting amount of water droplets from the snow making nozzle  11 . 
     The shape of the catching unit  60  is not limited to a rectangular shape, and other shapes may be adopted. For example, the shape of the catching unit  60  may be a shape such as a trapezoidal shape where an end portion of the drum  20  positioned on an outer side in a radial direction is longer than an end portion of the drum  20  positioned on an inner side in a radial direction. In this case, the catching unit  60  is attached to the frame  61  in a state where a radially outer portion of the catching unit  60  is slackened. Accordingly, the catching unit  60  is shaken by blowing off compressed air or the like to the catching unit  60 . On the other hand, since a radially inner portion of the catching unit  60  is attached to the frame  61  in a stretched state, the catching unit  60  is less likely to be shaken. As a result, it is possible to suppress interference between catching units  60  disposed adjacently to each other around the rotary shaft  72 . The shape of the catching unit  60  is not limited to a trapezoidal shape, and may be a shape including a curved portion in a profile of the shape. 
     In a case where the inlet of the snow making duct  12  is open, the open space may be cooled or may be at a room temperature. 
     It should be construed that the exemplary embodiments disclosed in this specification are illustrative in all aspects, and are not limitative. The scope of the present invention is not limited by the above-mentioned description but is limited by the claims, and it is intended that the scope of the present invention includes all modifications within the meaning and the scope equivalent to the claims. 
     The above-mentioned exemplary embodiments are recapitulated as follows. 
     (1) The snow making apparatus according to the exemplary embodiment includes: the snow making container having the inner space for snow making; the supply unit configured to supply fine snow or fine water droplets to the inner space; the catching units for catching the fine snow or fine snow formed from the water droplets; and the drive unit configured to move the catching units toward the place where the fine snow is flying in the inner space. The catching unit is configured to be shaken thereby making snow caught by the catching unit fall off from the catching unit. 
     According to the snow making apparatus, the drive unit moves the catching units toward the place where the fine snow is flying in the inner space of the snow making container and hence, the fine snow can be efficiently attached to the catching units. As a result, the fine snow is easily stacked in the catching units and hence, it is possible to efficiently form agglomerated-snowflakes as compared with conventional snow making apparatuses. Further, even in a state where the fine snow is flying in the snow making container, the fine snow can be efficiently caught. 
     In the above-mentioned exemplary embodiments, “fine snow” caught by the catching unit includes not only the fine snow itself supplied from the supply unit or the fine snow itself formed from the water droplets supplied from the supply unit, but also the fine snow grown by being bonded to each other in the inner space of the snow making container. 
     (2) In the above-mentioned snow making apparatus, the catching units may be configured to fall off the snow from the catching units by being shaken by wind pressure from the supply unit. 
     With such configuration, the supply unit has a function of shaking the catching units, it is not necessary to provide a configuration for shaking the catching units other than the supply unit. Accordingly, configuration of the snow making apparatus can be simplified. 
     (3) The snow making apparatus according to the above-mentioned embodiment includes: the snow making container having the inner space for snow making; the supply unit configured to supply fine snow or fine water droplets to the inner space; the catching units for catching the fine snow or fine snow formed from the water droplets; the drive unit configured to move the catching units toward a place where the fine snow is flying in the inner space; and the fall-off unit configured to make snow caught by the catching units fall off from the catching units. 
     With such configuration, it is possible to make the fine snow flying in the inner space of the snow making container efficiently adhere to the catching units. Accordingly, agglomerated-snowflakes can be efficiently made. Moreover, the snow caught by the catching unit can be made to fall off from the catching unit by the fall-off unit and hence, a snowfall environment of agglomerated-snowflakes can be efficiently created. 
     (4) In the above-mentioned snow making apparatus described above, the drive unit may be configured to rotate the rotary shaft that supports the catching units, and in this case, the catching units may be movable due to rotation of the rotary shaft by the drive unit. 
     With such configuration, the snow making apparatus can efficiently catch the fine snow flying in the inner space of the snow making container with the simple device configuration. 
     (5) In the above-mentioned snow making apparatus, the supply unit is configured to supply the fine snow or the water droplets toward the region where the catching units rotate and pass in the inner space. 
     With such configuration, the fine snow supplied from the supply unit or the fine snow formed from the water droplets supplied from the supply unit is easily directly caught by the catching unit. Accordingly, it is possible to efficiently make agglomerated-snowflakes in the catching units. 
     (6) In the above-mentioned snow making apparatus, the plurality of catching units including the catching unit may be disposed around the rotary shaft. 
     With such configuration, the plurality of catching units are provided and hence, a catching area can be increased whereby the fine snow flying in the inner space of the snow making container can be efficiently caught. 
     (7) The snow making apparatus may further include the support members that support each catching unit. The catching unit may be supported by the support member in a slackened state. 
     With such configuration, the catching unit can be easily shaken and hence, it is possible to easily fall off agglomerated-snowflakes from the catching unit. 
     (8) In the snow making apparatus described above, the supply unit may include the snow making nozzle configured to jet the water droplets, and the snow making duct that guides the fine snow formed from the water droplets jetted from the snow making nozzle to the inner space. 
     With such configuration, it is possible to secure a long distance between the snow making nozzle and the catching units as compared with a case where the snow making nozzle is disposed in the snow making container. Accordingly, it is possible to suppress snow made of coarse ice particles from being caught by the catching units. 
     (9) The above-mentioned snow making apparatus may further include the snow adhesion preventing unit that prevents the fine snow from adhering to the inner surface of the snow making duct. 
     With such configuration, it is possible to suppress clogging of the snow making duct by the snow. 
     (10) In the above-mentioned snow making apparatus, the snow making duct may include the outflow port through which the fine snow is made to flow out, and the outflow port may open toward the region where the catching units passes. 
     With such configuration, the fine snow flowing out from the snow making duct is caught by the moving catching units and hence, the snow is more easily stacked on the catching units. 
     (11) The above-mentioned embodiment discloses the snowfall test apparatus that includes the test chamber and the snow making apparatus for making snow to be supplied to the test chamber. 
     As is apparent from the description made heretofore, the present invention can provide a snow making apparatus capable of efficiently making agglomerated-snowflakes. 
     This application is based on Japanese Patent Application No. 2021-4842 filed on Jan. 15, 2021, the contents of which are hereby incorporated by reference. 
     Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention hereinafter defined, they should be construed as being included therein.