Patent Publication Number: US-6334327-B1

Title: Snowmaking machine

Description:
FIELD OF THE INVENTION 
     The present invention relates to an artificial snow making equipment for an artificial ski slope wherein a block of ice is pulverized and blown away. 
     RELATED ART 
     A conventional air-blowing pulverizer such as an ice crusher generates artificial snow  49  by pulverizing ice block  48  into sleet-like small pieces as shown in FIGS. 11 and 12. The equipment in FIG. 11 has rotary blades  45  for pulverizing which are arranged at an equal distance from each other in the radial direction around the rotational shaft in casing  44  on the top of rigid substrate  47 . Air supply opening  41 , through which air to glow artificial snow  49  is supplied, and ice supply opening  42 , through which ice blocks are supplied, are placed at one end of substrate  47  under the lower end of casing  44 . The other end of substrate  47  under casing  44 , opposite from supply opening  42 , has exhaust opening  43  through which artificial snow  49  made of pulverized ice is blown. Ice blocks  48  are supplied, together with air through air supply opening  41  on the substrate at the right side in the figure and are pulverized into sleet-like pieces by crushing them against substrate  47  with the rotational force of rotary blades  45 , which are arranged around rotational shaft  46  and rotate at 
     Another example of a conventional air-blowing pulverizer is shown in FIG.  12 . Herein, the positions of supply opening  42  for ice blocks and air supply opening  41  are different from ones in FIG. 11 wherein they are arranged at separate positions on casing  44 . Supply opening  42  for ice blocks  48  is placed at the top of casing  44 . Supplied ice blocks, while passing through casing  44  by rotary blades  45  for pulverizing which are rotated by rotational shaft  46  at a high speed, are crushed with rotary blades  45  and reach the air supply opening at the bottom of casing  44 . The crushed ice is further pulverized between substrate  47  and rotary blades  45  to be artificial snow  49  which is blown with air through exhaust opening  43  at the other end of the bottom of casing  44 . 
     However, the above air-blowing pulverizer has drawbacks. With the pulverizer of FIG. 11, the size of ice pieces pulverized by rotary blades  45  may vary depending on the amount of ice blocks  48  supplied to casing  44  through supply opening. Also, once the supply of ice blocks  48  becomes excessive, the path between air supply opening  41  and exhaust opening  43  may become blocked with snow. Therefore, excess drive is required to rotate rotary blades  45  at a high speed. With the pulverized of FIG. 12, in addition to the drawbacks discussed about the pulverizer in FIG. 11, when one intensifies the air flow through air supply opening  41  to blow the pulverized ice pieces further, not all the air reaches exhaust opening  43 , but some air flows backward and tends to leak from supply opening  42 . As a result, the air flow to blow artificial snow  49  from exhaust opening  43  is weakened such that artificial snow  49  cannot be blown far enough. Consequently, further drive is required. 
     Hence, the present invention intends to provide an efficient air-blowing pulverizer in which: 
     variance in the size of pulverized ice pieces is eliminated by stabilizing the amount of ice blocks to be supplied such that the resulting artificial snow is more desirable for skiing; 
     operation of the pulverizer is smoothly continued by preventing ice blocks from blocking inside the casing; and 
     all supplied air can be utilized to blow the pulverized ice pieces far enough without requiring excess drive. 
     DESCRIPTION OF THE INVENTION 
     To serve the above purpose, the present invention provides, according to the first invention, an artificial snow making equipment with constant forced-blowing, comprising: 
     an ice block supplier  1  to supply ice blocks at a constant rate including: 
     a casing  3  having, on a upper side of the casing, an ice block supply opening  4  through which ice blocks  2  are supplied, and on a lower side of the casing, an exit for ice blocks  5  which is positioned under the casing  3 ; 
     a rotary blades  8  which are arranged at an equal distance from each other around a rotational shaft  6 , formed at the center of the casing  3 , to supply the ice blocks  2  at a constant rate; and 
     an air-blowing pulverizer  11  including: 
     an air duct  9  which receives the ice blocks  2  and air  12  being supplied from an ice block supplier  1 ; 
     a casing  13  having an opening  10  of the air duct  9  on the side surface; 
     rotary blades  17  radially arranged at an equal distance from each other around periphery  16  of rotational shaft  15 , formed at the center of the casing  13 , to pulverize ice blocks  2  into ice pieces  18 ; and 
     an air exhaust  19  formed on the opposite side of the casing  13  from the opening  10  of the air duct to blow ice pieces  18  as artificial snow  20 , 
     wherein the exit for ice blocks  5  of the ice block supplier  1  is connected to an ice block receiving slot  14  of air-blowing pulverizer  11  by the air duct  9 . 
     According to the second invention in reference to artificial snow making equipment with constant forced-blowing of the first invention, the ice block supplier  1  is such that space  22  between the periphery of casing  3  and edge  21  of rotary blade  8  is formed to be very narrow to prevent a back flow of air  12  from exit for ice blocks  5  into the ice block supplier  1 . 
     According to the third invention in reference to artificial snow making equipment with constant forced-blowing of the first or second invention, the rotary blades  17  of the air-blowing pulverizer  11  have width  24  equal to the length  23  of rotational shaft  15 , and the rotary blades  17  are radially arranged at an equal distance from each other around the periphery  16  of the rotational shaft such that rotary blades  17  are parallel to axis  39 . 
     According to the fourth invention in reference to artificial snow making equipment with constant forced-blowing of the first or second invention, the rotary blades  17  in the air-blowing pulverizer  11  are radially arranged in two rows at an equal distance from each other around the periphery  16  of the rotational shaft, wherein one side of the rotary blades  17 , at the central periphery  26  of the shaft, is positioned behind the other side of the rotary blade  17 , on an edge  25  of the shaft, in the direction opposite from direction of rotation  27  such that rotary blade  17  is oblique to axis  39 . 
     According to the fifth invention in reference to artificial snow making equipment with constant forced-blowing of the second or fourth invention, edge portion  31  is a portion of rotary blade  17  in air-blowing pulverizer  11  between edge  29  of the blade and bending line  30  which is located between base  28  and edge  29  of the blade wherein edge portion  31  is bent in the direction opposite from direction or rotation  27 . 
     In other words, the means of the present invention has an ice block supplier  1  to supply ice blocks as a raw material at a constant rate to air-blowing pulverizer  11 . In this an ice block supplier  1 , a plurality of rotary blades  8  are arranged at an equal distance from each other around rotational shaft  6  which rotates inside casing  3 . Exit for ice blocks  5  of an ice block supplier  1  to supply ice blocks at a constant rate is placed facing air duct  9  through which air is forced to air-blowing pulverizer  11  such that ice blocks can be supplied to air-blowing pulverizer  11  at a constant rate by adjusting the speed of rotation of rotary blades  8  in relation to the volume of the space between rotary blades  8 . Additionally, space  22  between the [inner] periphery of casing  3  and edge  21  of rotary blade  8  is established to be a minimum yet does not cause any disturbance in the rotation of rotary blades  8 . This configuration prevents the force of air to air-blowing pulverizer  11  from declining, which is caused by a backflow of air to be supplied to air-blowing pulverizer  11  into ice block supplier  8  to supply ice blocks at a constant rate via exit for ice blocks  5  of an ice block supplier  1  as an opening to supply ice blocks to air-blowing pulverizer  11 . 
     In air-blowing pulverizer  11 , a plurality of rotary blades  17  are arranged in the radial direction around rotational shaft  15  which rotates in cylindrical casing  13  at a high speed. Air duct  9  is placed facing the side of casing  13  to form ice block receiving slot  14  which receives ice blocks  2  to be pulverized, as well as forced air. The side of casing  13  opposite from ice block receiving slot  14  is air exhaust  19  through which artificial snow made of pulverized ice pieces  18  is blown out. 
     In the case of air-blowing pulverizer  11  where rotary blades  17  are alternated in two rows around rotational shaft  15 , blade  32  is positioned between one edge  25  of rotational shaft  15  and central periphery  26  of the shaft while blade  33  is positioned between central periphery  26  and the other edge  25 . This plurality of blades is alternated in two rows on periphery  16  of the rotational shaft. As a result, ice blocks  2  to be pulverized move between rotary blades  17  from left to right and vice versa as they are transferred to air exhaust  19  such that ice pieces  18  will not block the space between rotary blades  17 . This configuration does not require extra drive [as a counter force against the blocked path]. Further, ice blocks  2  are pulverized by rotary blades  17  while moving between rotary blades  17 , resulting in more uniformed small ice pieces  18  as artificial snow  20 , more appropriate for skiing. Moreover, the side of rotary blades  17  in two rows at central periphery  26  of the shaft is positioned to form an angle alpha in relation to rotational shaft  15  in the direction opposite from the direction of rotation. Consequently, ice blocks  2  can more easily move between two rows of rotary blades  17  such that the pulverizing performance is improved. Additionally, a backflow of the air in casing  13 , which would cause a decline in the air pressure, is prevented such that artificial snow  20  can be blow further away. 
    
    
     BRIEF DESCRIPTIONS OF DRAWINGS 
     FIG. 1 is a schematic configuration showing artificial snow making equipment with constant forced blowing of the present invention. 
     FIG. 2 is an oblique view of one row of rotary blades in an air-blowing pulverizer according to the present invention. 
     FIG. 3 is an oblique view of two rows of rotary blades in an embodiment of the present invention. 
     FIG. 4 is a plan view of the rotary blades in FIG.  3 . 
     FIG. 5 is an profile view of FIG.  3 . 
     FIG. 6 is an expanded plan view of a rotational shaft and rotary blades. 
     FIG. 7 is an oblique view of another embodiment of FIG. 2 wherein the edge portion of the rotary blades are bent. 
     FIG. 8 is an oblique view of another embodiment of FIG. 3 wherein the edge portion of the rotary blades are bent. 
     FIG. 9 is a plan view of the rotary blades in FIG.  7 . 
     FIG. 10 is an profile view of the rotary blades in FIG.  7 . 
     FIG. 11 is a side view of a schematic configuration of conventional air-blowing artificial snow making equipment. 
     FIG. 12 is a side view of a schematic configuration of another conventional air-blowing artificial snow making equipment. 
    
    
     In these figures, following symbols are used: 
       1 : ice block supplier to supply ice blocks at a constant rate; 
       2 : ice blocks; 
       3 : casing; 
       4 : ice block supply opening; 
       5 : exit for ice blocks; 
       6 : rotational shaft; 
       7 : periphery of rotational shaft; 
       8 : rotary blades; 
       9 : air duct; 
       10 : opening of air duct; 
       11 : air-blowing pulverizer; 
       12 : air; 
       13 : casing; 
       14 : ice block receiving slot; 
       15 : rotational shaft; 
       16 : periphery of rotational shaft; 
       17 : rotary blades; 
       18 : ice pieces; 
       19 : air exhaust; 
       20 : artificial snow; 
       21 : edge; 
       22 : space; 
       23 : length of shaft; 
       24 : width; 
       25 : edge of shaft; 
       26 : central periphery of shaft; 
       27 : direction of rotation; 
       28 : base of rotary blade; 
       29 : edge of rotary blade; 
       30 : bending line; 
       31 : edge portion of rotary blade 
       32 - 38 : blade; 
       39 : axis; 
       40 : shifting direction; 
       41 : air supply opening 
       42 : ice supply opening; 
       43 : exhaust opening; 
       44 : casing; 
       45 : rotary blades 
       46 : rotational shaft; 
       47 : substrate; 
       48 : ice blocks; 
       49 : artificial snow 
       50 : angle alpha; 
       51 : angle beta; 
     EMBODIMENTS 
     The following describes embodiments of the present invention in reference to the drawings. FIG. 1 is a schematic configuration of the present invention showing artificial snow making equipment with constant forced blowing wherein the front wall is removed to show the inside configuration. Number  1  is an ice block supplier to supply ice blocks at a constant rate, placed on the upstream side of air-blowing pulverizer  11 . An ice block supplier  1  to supply ice blocks at a constant rate has funnel-shaped ice block supply opening  4 , which receives ice blocks  2  as a raw material, on the top of steel cylindrical casing  3 . In casing  3 , rotational shaft  6  is positioned at the center and is rotated by a drive (not show in the figure) in the direction indicated by an arrow. With rotary blades  8  comprised of six steel blades, the width of each blade is equal to the width of rotational shaft. Additionally, the blades reach the inner wall of casing  3  and are arranged at an equal distance from each other in the radial direction around periphery  7  of rotational shaft  6 . Exit for ice blocks  5 , having a width equal to the distance between blades, is positioned at the bottom of casing  3 . 
     Exit for ice blocks  5  of an ice block supplier  1  to supply ice blocks at a constant rate is connected to the side of air duct  9  through which air  12  is sent into air-blowing pulverizer  11  at the bottom of an ice block supplier  1  and functions as ice block receiving slot  14  of air-blowing pulverizer  11 . After obtaining ice blocks  2  through ice block receiving slot  14 , ice blocks are transferred together with air  12  via air duct  9  through opening  10  of air duct, connected to the side of cylindrical steel casing  13 , into air-blowing pulverizer  11 . Rotational shaft  15  is placed at the center of casing  13  and is driven by a drive (not shown in the figure) at a high speed in the direction indicated by the arrow. Rotary blades  17  composed of steel are arranged at an equal distance around periphery  16  of rotational shaft  15  in the radial direction. Air exhaust  19 , through which ice pieces  18  pulverized in casing  13  are blown with forced air as artificial snow, is placed at the side of casing  13  opposite from opening  10  of the air duct. 
     In an ice block supplier  1  to supply ice blocks at a constant rate, space  22  between edge  21  of rotary blades  8  and the inside wall of casing  13  is established to be a minimum without disturbing the rotation of the blades. As a result, air  12  is prevented from flowing from exit for ice blocks  5  to an ice block supplier  1  via space  22 . 
     There are various modifications of rotary blades  17  of air-blowing pulverizer  11 . The following describes those modifications in reference to drawings of rotary blades  17 . FIG. 2 illustrates rotary blades  17  that have width  24  equal to length  23 , between edge  25  and another edge  25  of rotational shaft  15  wherein six rotary blades  17  are arranged at an equal distance from each other around periphery  16  of rotary shaft  15  in parallel to axis  39 . In this case, ice blocks  2 , which are supplied from opening  10  of the air sending duct on the side of casing  13 , are pulverized by being crushed by one of rotary blades  17  in rotation. The ice blocks are further pulverized by friction against each other to become ice pieces  18 . Ice pieces  18  are pushed by rotary blades  17  during the rotation and blown out through air exhaust  19 . 
     The following describes rotary blades  17  of another embodiment in reference to FIG.  3 . Two rows of rotary blades, which have a width equal to the distance from one edge  25  of the shaft to central periphery  26  of the shaft, are arranged at an equal distance from each other in parallel to axis  39  wherein positions of rotary blades  17  in the left row and the right row are alternated. Herein, rotary blade  17  is not adjacent to the center of another rotary blade  17  on periphery  16 . Therefore, ice blocks  2 , which are inserted from opening  10  of the air duct on the side of casing  13 , are placed in front of rotating rotary blade  17  and crushed therewith. Ice blocks  2  are then pushed by rotary blade  17  to the space on periphery  16  of the shaft in the adjacent row. Accordingly, ice blocks shift between rotary blades  17  in the left and right rows during the rotation such that the ice blocks are further pulverized by the blades. Together with pulverization due to the friction among the ice blocks, ice pieces  18  with uniform small particles result. 
     FIGS. 3 through 6 show rotary blades  17  of yet another embodiment. Herein, the center sections of rotary blades  17  in two rows are shifted backward in relation to the sides on edges  25  of the shaft in the direction opposite from the direction of rotation  27  with angle alpha in relation to axis  39  of rotational shaft  15  while rotary blades  17  of two rows are arranged parallel to axis  39  in the above embodiment. FIG. 4 is a plan view of rotary blades  17  in FIG. 3 while FIG. 5 is an profile view of rotary blades  17  in FIG. 3. A dotted line in FIG. 4 indicates rotational shaft  15 . In FIG. 5, blades  32 ,  35  and  36  are positioned on the closer side of rotary shaft  15  as shown in FIG. 3 wherein the side of the blades at central periphery  26  is shifted backward in relation to the side of edge  25  with angle alpha in relation to axis  39 . Similarly, blades  33 ,  34 ,  37  and  38  are positioned on the further side of rotary shaft  15  wherein the side of the blades at central periphery  26  is shifted backward in relation to the side of edge  25  with angle alpha in relation to axis  39 . Blades on either side are angled at the center section in the direction opposite from direction of rotation  27 . FIG. 6 is an expanded plan view of rotational shaft  25  and rotary blades  17 . 
     When rotary blades  17  of FIG. 5 rotate in the direction of rotation  27  as in FIG. 6, ice blocks  2  shift between the blades in two rows (top and bottom rows in the figure) in shifting direction  40 , as indicated with an arrow. Ice blocks  2  are crushed by the blades every time they are shifted therebetween, resulting in ice pieces  18  which move in the direction of rotation  27  and are blown out from air exhaust  19 . In other words, after being crushed by blade  37 , ice blocks  2  shift along the arrow and are further pulverized by blade  35 . The pulverized ice blocks are shifted to blade  33 , then blade  32  to be further pulverized resulting in ice pieces  18  which moves in shifting direction  27  and are blown out from air exhaust  19 . 
     Yet another embodiment is shown in FIGS. 7 through 10. FIG. 7 is a modification of rotary blades  17  of FIG.  2 . FIG. 8 is a modification of rotary blades  17  in two rows of FIG.  3 . In these embodiments, bending line  30  is established from base  28  to edge  29  of rotary blade  17  wherein edge section  31  of rotary blade  17  nearest the edge is bent at bending line  30  with angle beta in direction of rotation  27 . FIG. 9 is a plan view of the rotary blades of FIG. 7 while FIG. 10 is an profile view of FIG.  7 . By bending edge portion  31  of the rotary blades in direction of rotation  27 , ice blocks  2  supplied from opening  10  of the air duct into air-blowing pulverizer  11  are crushed by rotary blades  17  with more force to produce finer ice pieces  18 . As a result, artificial snow  20 , which is more suitable for skiing, can be obtained. 
     The following further describes the artificial snow making equipment and its operation. Ice blocks to be used with an ice block supplier  1  to supply ice blocks at a constant rate are plate ice prepared with an ice machine in advance and have a size of 7 mm thickness×50 mm×100 mm. The speed of rotation of rotary blades  8  in an ice block supplier  1  is established at 25 rpm such that the ice blocks are supplied to air-blowing pulverizer  11  together with forced air from air duct  9 . The force of the forced air from air duct  9  is established to be strong enough to blow out artificial snow  20  made of ice pieces  18 , which are pulverized with air-blowing pulverizer  11 , through air exhaust  19  at the wind speed of 30 m/sec. In other words, the speed of rotation of rotary blades  17  of air-blowing pulverizer  11  is established to be a high speed of 1500 to 1600 rpm. The performance of air-blowing pulverizer  11  to process artificial snow  20  is 20 m 3 /min. Additionally, rotary blades  17  in two rows between edge  25  of the shaft and central periphery  26  of the shaft are angled in relation to axis  39  by 10 to 15 degree. The diameter of rotary blades  17  of air-blowing pulverizer  11  is 700 mm, and length  23  is 190 mm. In the case of rotary blades  17  which have their edge  31  bent at bending line  30 , the radius between the center of the shaft to bending line  30  of the rotary blades  17  is established to be 250 mm. In addition, the number of rotary blades  17  in each row on the shaft periphery is 6. The size of ice pieces  18  produced by air-blowing pulverizer  11  is sleet-like ice used for snow-cones. Ice pieces  18  are blown out through a hose of about 50 m at air exhaust  19  of air-blowing pulverizer  11  onto a ski slope as artificial snow  20 . 
     Application in the Field 
     As described above, the present invention of the artificial snow making equipment with constant forced blowing has an ice block supplier which supplies ice blocks to an air-blowing pulverizer at a constant rate at the upstream of the air-blowing pulverizer. As a result, pulverization by rotary blades of the air-blowing pulverizer is uniformly performed such that the size of pulverized ice pieces is uniform. Additionally, ice blocks are supplied at a constant rate, preventing any blocking of the space between the rotary blades due to excess supply, such that a sudden stop of the air-blowing pulverizer is preventable. Further, any excess drive is not required to rotate the rotary blades against the force. In addition, a decline in the force of air, due to a back flow of forced air into the ice block supplier to supply ice blocks at a constant rate, can be prevented. In the air-blowing pulverizer, an ice block supply opening is placed to connect to an opening of an air duct. Therefore, the air, forced together with ice blocks from the opening of the air duct, is used only for blowing the artificial snow through the air exhaust. Consequently, a loss in air-pressure is minimized such that the artificial snow can be blown to the requisite distance. Additionally, two rows of the rotary blades are alternated around a rotational shaft such that ice blocks are strongly pulverized by a plurality of rotary blades while shifting between the alternated rotary blades, resulting in high pulverization performance. Hence, a large amount of excellent artificial snow with uniform particles can be produced. Further, the rotary blades are angled in relation to the axis of the rotational shaft such that the center side of the rotary blades are shifted backward such that the ice blocks can be shifted among the rotary blades more smoothly. As a result, the ice blocks are efficiently crushed by the rotary blades which increases the pulverization performance. Moreover, since the edge of the blades are bent in the direction of rotation, the blades can pulverize the ice blocks with more force. Therefore, finer and more uniformed ice pieces can be effectively produced. These effects are not obtained by conventional technology.