Abstract:
A snow making spray head that can be adapted to a snow tower is disclosed. The spray head is designed to be rotatable about a vertical axis without having to rotate the tower itself so that the direction of the spray can be adjusted to effectively lay down quality snow onto the trail in an effective pattern under different wind directions.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates generally to the art of snow making and to an improved method and apparatus for making large volumes of high quality machine-made snow suitable for skiing, and more particularly to adjustable tower-type snowmakers having a novel rotatable spray head which improves the snow making ability of such towers. 
       BACKGROUND OF THE INVENTION 
       [0002]    The invention described herein relates to the art of producing machine-made snow and particularly to a novel rotatable spray head that can be used on practically any design of snow tower to improve the making of snow wherein compressed air and water under pressure comprise the two main ingredients used to make the snow. 
         [0003]    Numerous water spray systems have been developed for producing snow wherein water and air under pressure are, in some manner, commingled. The principle involved is to reduce the size of water particles to a very small and consistent size, typically by high pressure discharge of water through an atomizing nozzle orifice to form a spray, and augmented by injection of compressed air directly or indirectly with the water spray or mixing with air within a mixing chamber, to thereby form seed crystals. These seed crystals then mix with the water spray and freeze as they fall from the spray head through the cold ambient air. 
         [0004]    Machine-made snow is formed from seed crystals. Preferably, these seed crystals are formed from the expansion of compressed air expelled into the atmosphere within and around which minute water particles freeze and form machine-made snow. The compressed air is at a higher temperature than normal ambient winter air conditions and when expelled to ambient will expand to atmospheric pressure while simultaneously dropping greatly in temperature. Of course, impingement of the expanding compressed air stream upon associated atomizing-spray-generated water particles also forms such seed crystals. These seed crystals are immediately formed because of the extremely low temperature condition obtained through the expansion of the air together with the freezing effect of atmospheric conditions of winter, that is, wet bulb temperatures below 32° F. The seed crystals thus formed can be combined with the remaining water particles of the atomized water spray in a manner to form more machine-made snow. 
         [0005]    In connection with the atomizing of water for snow making it has long been known that the water particle size should be small and consistent, in many cases as small as 200 microns or less. If such particles are too large, depending on ambient weather conditions and the ratio of water to air mixture, they will produce ice or sleet particles which are not frozen or seeded properly and are unsatisfactory for desirable skiing conditions. Also, the greater the water pressure at the discharge nozzle, the smaller the water particles or moisture droplets upon nozzle discharge. However, the water particles should not be so small that they drift away, evaporate and/or sublimate. 
         [0006]    Additional information and history of various methods and apparatus for making snow are set forth in columns 1 through 8 of the Kircher et al. U.S. Pat. No. 6,161,769, and in the references cited therein, all of which are incorporated herein by reference. 
         [0007]    Other examples of United States patents directed to spray snow making pipe towers are as follows (also all incorporated “herein” by reference): McKinney U.S. Pat. No. 5,810,251; Dupre U.S. Pat. No. 5,908,156; McKinney U.S. Pat. No. 5,979,785; Pergay et al. U.S. Pat. No. 6,508,412; Dupre U.S. Pat. No. 6,543,699 and Jervas U.S. Pat. No. 6,547,157. 
         [0008]    Over the years many apparatus and techniques have been developed for generating machine-made snow thus increasing the number of days of the season for snow skiing and the like. The art of making machine-made snow is well documented. 
         [0009]    U.S. Pat. No. 6,161,769 and the references cited therein, especially in columns 1 through 8, give a good background of apparatus and methods that have been used to generate machine-made snow. Three main techniques are generally used; lower energy snow towers having a spray head located at the top, fan driven snow makers and higher energy portable snow making apparatus. 
         [0010]    Various spray head designs and snow towers have been developed to assist in making better snow in various climate conditions. U.S. Pat. Nos. 7,290,722: 6,719,209: 6,508,412 are examples of snow making towers and spray heads that can be improved by practicing the principles of the invention described and claimed herein. 
         [0011]    One of the challenges with making snow is wind direction. It is generally preferred to disperse the initial seeds in the same direction as the wind to permit proper seed and water mixing along with providing a long dwell time that improves the quality of the snow. Making snow in the direction of the wind allows the water droplets and seed crystals adequate time to form, shape, and mix and freeze while falling through the cold ambient air. The wind direction can also affect the ability of the water and air nozzles to produce fine droplets of water without freezing up. Cold wind directions and velocities often change. Tower snow makers are primarily located on the windward trail edge for safety on the slopes, convenience for the operators and to allow the winds to carry the snow across the trail. The trail orientation may be designed and built with the natural topography such that the trail changes directions and aspect so that the typical cold winds may blow up or down the trail as opposed to across the slope. Cold wind direction and wind velocity often change during snowmaking. Some ski resorts will place fixed position tower snow guns in the middle of the ski slopes to allow the head position to have the wind behind the snow gun in any wind condition. However, narrow trails, aesthetics and safety aspects of placing fixed objects in the middle of ski slopes cause resorts to place these fixed snow towers more typically on the windward trail edge.  FIG. 8  shows a fixed tower  50 , located on the edge of a ski trail and leaning over the ski trail. The general pattern of snow laid down is shown as  51 , when the wind  52  is blowing from behind the tower  50 , and generally across the trail. The snow towers commonly used today can be pivoted 360° in the horizontal plane using the tube on post method. This allows full flexibility to rotate the tower itself. The snow gun tower and head can also be raised and lowered between horizontal 0° and upright to 90°.  FIGS. 9 and 10  are views of the trail looking down from above.  FIG. 9  illustrates two conditions when the wind  53  is blowing down the trail. When the tower is in the first position as illustrated by the solid lines, and is provided with the rotating snow head,  58 , of the invention and is rotated so that the nozzles are facing downhill (i.e. downwind), the snow pattern  54  that is formed is still good and covers the trail with good snow. When the entire snow tower (with the prior art head) is rotated, indicated by the dashed lines, in an attempt to take advantage of the nozzles of the fixed head facing somewhat downhill the rotation now brings the head nearer to the edge of the trail and the pattern  55  of the deposited snow is inadequate to cover the width of the ski trail. 
         [0012]    In  FIG. 10  an ordinary spray tower with a fixed head is left in its normal position even though the wind is coming down the trail. This position causes additional problems. With winds blowing across the snow gun head the water and seed droplets formed by the snow head are forced out of the natural designed direction so they no longer mix and collide properly. Larger water droplets are formed much earlier and closer to the snow gun head, seed crystals collide faster and cause bigger and abnormal shapes that do not freeze as thoroughly. Crosswinds result in much lower freeze rates than normal, reducing snow production considerably and/or often resulting in wetter snow or ice slicks on the slopes as indicated by the shaded area  56  of the deposited snow pattern and a smaller snow pattern  57 . As previously indicated when referring to  FIG. 9 , rotating the tower assembly in the horizontal plane to position the head with a tail wind may reduce the negative effects of mixing and freezing associated with cross winds. However, the disadvantages of rotating the tower assembly include, but are not limited to, a less desirable snowmaking zone on the trail and snowmaking off trail, see  FIG. 9 .  FIG. 8  illustrates a snow making assembly aligned perpendicularly to the trail with a cross trail tail wind  52 . This is an ideal snowmaking condition for trail edge mounted towers as it projects the head and plume over the trail to produce a desirable landing zone. Because the boom typically extends out over the trail at an angle less than 90 degrees to horizontal, rotating the tower will reduce the over-hang onto the trail,  FIG. 9 . In the case of a down trail crosswind, the boom would need to be rotated nearly off trail to position the plume in a favorable snowmaking wind condition. The invention allows the boom to protrude to its fullest extent over the trail and the head and plume to be rotated to a position that allows the tower to be used to its optimal effectiveness in wind conditions other than a tail wind. Sometimes when the wind direction is either down the slope or up the slope an attempt to make new snow with standard snow towers is not even attempted. 
         [0013]    In the situations in which the tower is permanently at a fixed location, the ability to pivot the snow spray head to spray up or down the trail so that the wind stays behind the snow gun plume would offer many benefits. 
         [0014]    The invention disclosed and claimed herein concerns a novel spray head and its use on practically any tower snowmaking apparatus with the result that the problems caused by changing wind directions are reduced. 
       SUMMARY OF THE INVENTION 
       [0015]    The novel snow making spray head of the present invention comprises a rotatable body having spray nozzles that disperse water and nucleated water droplets said body forming at least two internal channels providing water and or water and air to such nozzles, said spray head being functionally connected to a tower supplying pressurized water and compressed air to the spray head. The spray head is attached to the end of the tower in an angular relation such that when the tower is positioned vertically to it&#39;s generally production angle, e.g. about 60 degrees from vertical, the spray nozzles generally spray in a horizontal direction. Generally when in use the axis of the spray head aligns vertically. In operation, the rotating portion is rotated to position the nozzles preferably facing away from the wind direction and in a horizontal direction to maximize the pattern and quality of the machine-made snow. A specific spray head embodiment design is described herein. In addition known stationary spray heads such as taught in U.S. Pat. Nos. 7,290,722; 6,719,209 and 6,508,412 can be adapted to rotate employing the principles of the present invention thus providing the advantages of the present invention. The novel spray head can be fitted to standard snow making towers known in the art such as described in U.S. Pat. No. 6,161,769 and the like. The teachings of these patents are specifically incorporated herein by reference. The spray head is functionally attached to well known types of snow towers in any conventional manner, such as by bolting, welding and the like. 
         [0016]    One embodiment of the spray head comprises, a fixed cap, a fixed base, an adjustable rotatable hollow body fixed between said cap and said base and rotatable about its axis to fixed positions and having at least two nozzles positioned therein, said head having at least two internal chambers communicating with said nozzles, at least one said channel functionally communicating with a source of compressed air in said base and at least one said channel communicating with a source of pressurized water, and said body rotatable about its axis while maintaining the communication between said chambers, said nozzles and said source of pressured water and compressed air in said base. The rotatable body can be rotated manually, mechanically (e.g. by winch/cable and the like), pneumatically, hydraulically or electrically or by other procedures. 
         [0017]    A second embodiment comprises a snow making spray head having a fixed base, an adjustable rotatable body fixed to said base and rotatable about its axis to fixed positions said body having at least two nozzles posited therein, said rotatable body having at least two internal chambers communicating with said nozzles, at least one of said channels functionally communicating with a source of compressed air from said base and at least one said channel communicating with a source of pressurized water, and said body rotatable about its axis while maintaining the communication between said chambers, said nozzles and said source of pressured water and compressed air in said base. If desired the spray head may be of any desired shaped such as, spherical, can shaped, cone, ellipsoid or the like. 
         [0018]    In a third embodiment the snow making spray head comprises; a body portion comprising a rotatable portion and a fixed portion, said rotatable portion affixed to said fixed portion such that it can be rotated around a common symmetrical axis to both portions, said rotatable portion having at least two separate internal chambers in fluid communication with at least two separate spray nozzles, one of said nozzles comprising a water spray nozzle and one of said nozzles comprising a spray nozzle dispensing nucleated water, said nozzles fixed in the outer wall of said rotatable portion and communicating with said chambers and the atmosphere; said rotatable portion also containing at least two internal conduits that communicate with said chambers and a source of pressurized water and compressed air; and said fixed portion including a fixed axle that is functionally adapted to said rotatable portion permitting the rotatable portion to rotate around said axle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Although the invention is illustrated through the use of the following Figures and the description thereof the invention is not limited to the specific embodiments illustrated there. Like parts are not numbered in all the Figures. 
           [0020]      FIGS. 1 and 2  show two views of one embodiment of the spray head of the invention as assembled. 
           [0021]      FIG. 3  shows an exploded view of one embodiment of the invention containing two columns of three nozzles each comprising two nucleating nozzles,  4   a , and four air dispersing nozzles  12  and  12   a  that disperse water droplets into the particles of very small seeds exiting the nucleating nozzles. The view is from the top and side. 
           [0022]      FIG. 3A  shows an exploded view from  FIG. 3  of the top portion of the pivot tube (axle)  2 . 
           [0023]      FIG. 4  shows an exploded view of the same embodiment as  FIG. 3  except from the bottom and side. 
           [0024]      FIG. 5  shows a side exploded cross section view of the spray head of the invention. 
           [0025]      FIG. 6  shows a cross section of the assembled spray head attached to the end of the boom of a snow making tower having one water pressure line surrounding a compressed air line. 
           [0026]      FIG. 6A  shows an enlarged portion  6 A from  FIG. 6 . 
           [0027]      FIG. 7  is a view taken from cut line  7  of  FIG. 6 . 
           [0028]      FIGS. 8 ,  9  and  10  Illustrate various snow quality and patterns based on the use of presently used snow towers and fixed spray heads compared with the improvement permitted by use of the claimed invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    The numbers referring to elements of the spray head have the following names. These names are for descriptive purposes and are not intended to restrict the invention to the exact names used. Equivalent elements can be used in the practice of the invention.
     1 —Head Base     2 —Head Pivot Tube (Axle)     3 —Head Rotating Body (Rotating Portion)     4  and  4   a —Nucleator Nozzles     5 —Head Plug     6 —Head Cap     7 —Rotating Body O-Ring     8 —Plug O-Ring     9 —Lower Air Chamber O-Ring     10 —Upper Air Chamber O-Ring     11 —Pivot Tube to Plug O-Ring     12  and  12   a  and  12 ′ and  12   a ′—Bulk Water Nozzles     13  and  13   a —Socket Head Cap Screws for Plug     14 —Socket Head Cap Screw for Pivot Tube     15  and  15   a —Nucleating nozzle O-Ring     16 —Dowel Pin     17 —Water ports through Base  2       18 —Rotating Limiting Groove Formed in Cap  6       19 —Antirotation Flats Pocket (Slot)     20  and  20   a —Anti Rotation Flats (Key)     21 —Underside face of base  1       22 —Threaded Hole for Cap Screw  14       23 —Water Orifices formed In Throttling Inserts  41  and  41   a        24  and  24   a  atomizing chambers formed in air passageways leading to Nozzles  4  and  4   a        25 —Air chamber formed by mating of a portion of the outer surface of Pivot Tube  2  with a portion of the inner surface of Rotating Body  3       26  and  26   a —Lower and upper water chambers respectively     27 —Air Inlet passageway formed in the interior of the Axle  2       28 —air passageway formed in the body of the axle  2  connecting the air Inlet tube passageway  27  with the air chamber  25       29 —Upper end of a boom of a snow making tower     30 —Water conduit formed in boom connecting spray head with a source of compressed water     31 —Compressed air conduit formed in boom connecting spray head with source of compressed air     32 —Mixture of compressed air and atomized water     33 —Common air channel formed in outer portion of the axle and communicating with air passageway     34 —Air communication tube formed in the interior of base  1       35 —Ports formed in rotating body  3  to hold nozzles and throttle inserts     36 —Ring shaped portion of surface of lower face of cap  6  when seated with body  3       37 —Upper face of body  3  (ring shaped) tube that mates with lower face  36  of cap  6  when head is assembled     38 —Threaded mounting holes formed in base  1  to permit attachment to upper face of a boom     39  and  39   a  O-rings fitting on air communication tube  34       40 —Boom flange O-ring     41  and  41   a —Throttling Nozzles (inserts)     42 —water passageways connecting lower water chamber  26 , with upper water chamber  26   a        43 —throttling orifice located at tip of throttling inserts,  41  and  41   a , causing atomization of water exiting from the throttling inserts and into atomizing chambers  24  and  24   a.      
 
         [0073]    As used in this application the following terms have the following meanings: 
         [0074]    Snow making tower means any of a variety of snow making apparatus having a boom that supports a snowmaking head, the boom containing means for transporting separately water and air under pressure from a source to the snow making head. 
         [0075]    Nucleation nozzle means nozzles that discharge a very fine mixture of water and air as seed crystals. The fine mixture can be formed internally within the nozzle or internally within the spray head and discharged through the nozzle. In the embodiment described herein the fine spray is formed internally within the rotating body through the use of throttle inserts that discharge a very fine spray of water under pressures into a stream of air moving at a high velocity in a mixing chamber (atomizing chamber) and the atomized seed particles are then dispersed out through the nucleating nozzle. 
         [0076]    A specific embodiment of a rotatable spray head is shown in the Figures and described in detail hereinafter. Although the embodiment is shown as being generally can shaped, the outside shape of the spray head is not a critical aspect of the invention. Snow heads as shown, for example, in U.S. Pat. Nos. 6,508,412; 7,290,722; 6719,209 and Publication US 2006/0079137 can be used. In fact the snow spray heads shown in these patents can be improved by practicing the principles of the present invention. 
         [0077]    Referring to  FIG. 1  and  FIG. 2  the spray head comprises a base  1  having an underside face  21  that is slanted at an angle such that when attached to the boom of a snowmaking tower the spray head will align essentially vertically and all the nozzles ( 12 , 12   a ,  12 ′ and  12   a ′ and  4  and  4   a ), will spray out in a generally horizontal direction when making snow. It is also possible to fix the nozzles in the head in a direction such that they align essentially horizontally while the axis of the head is not in a generally vertical direction. The head includes a rotating body  3  having at least one nucleating nozzle  4  and at least one water nozzle  12 . In the embodiment shown in the Figures there are provided two columns of nozzles aligned approximately 90 degrees apart with the nucleating nozzles  4  and  4   a  placed between two water nozzles  12  and  12   a  and  12 ′ and  12   a ′. Commercially available nozzles may be employed. The embodiment shown here also includes the use of two throttling nozzles (inserts)  41  and  41   a  that in conjunction with the compressed water and air form nucleated (atomized) water that is dispersed from the nucleating nozzles,  4  and  4   a  as a very fine spray of seed crystals. The throttling inserts use the well known principles in forming atomized water. The nozzles restrict the area through which the water flows thus increasing its pressure and velocity. The tip of the throttling inserts are cone shaped and upon release of the high velocity water into the cone shaped portion it rapidly expands in volume and in combination with flowing into a high velocity air stream forms atomized water droplets. 
         [0078]    The spray head can be constructed of any suitable material such as aluminum, steel, etc. 
         [0079]    Reference is made to  FIGS. 3 ,  3   a  and  4  for a more detailed description of the spray head. A pivot tube (axle)  2  having an axis that is symmetrically aligned with the axis of the base  1  and around which the rotating body  3  can rotate is fixed to and extends from said base a sufficient distance to provide an axle that supports and around which the rotatable body can be rotated to a desired position depending on wind direction. A compressed air inlet tube (passageway)  27  is formed in the interior of the axle that communicates with the compressed air tube  31  of the boom  29  through the base  1  via the air communication tube  34 . At least one port  28 , is formed in the wall of the axle that communicates with a common air channel  33  formed in the outer surface of the pivot tube (axle)  2 . When the head is assembled the rotating body  3  and the channel  33  form an air tight chamber  25  which communicates with nucleating nozzle  4  and  4   a  throughout a predetermine angle of rotation of the rotating body  3  (see  FIGS. 6A and 7  for these details). To form the atomized water that is released through the nucleating nozzles water passes through chamber  30  ( FIG. 6 ) into the water chamber  26  that is formed in lower portion of the rotating body,  3 , when the head is assembled. Water passes from the chamber  26  to a second chamber  26   a  through at least two water passageways  42  through the body portion  3  that feed the water nozzles  12   a  and  12   a ′. Two of these water passages also supply pressurized water to the throttling inserts  41  and  41   a  as shown in  FIG. 7 . Pressurized water passes through a cross hole  23  formed in the throttling inserts. The cross hole provides steady water flow to the throttling orifice  43  formed in the tip of the throttling inserts. The resulting water spray is injected into the pressurized high velocity air stream in the atomizing chamber  24  where it is atomized and expelled at a high velocity to the atmosphere through the nucleating nozzle  4 . The throttle insert causes the water to be expelled at a very high velocity into the stream of air that is also at a high velocity thus causing the atomization of the water into seed particles in the atomizing chambers  24  and  24   a . Each of the throttle inserts is securely fastened in the head  3  (such as by using a threaded mount in the ports they are inserted in) and contain a pair of 0-rings  15  and  15   a  to assure a water and air tight seal with the body  3 . The atomized water air mixture is then forced into and through the nucleating nozzles  4  and  4   a . If desired other means of forming the seed crystals can be employed. For example instead of using the throttling inserts the nucleating nozzle can be designed to connect with the compressed air stream and water stream and the water atomized internally within the nozzles  4  and  4   a.    
         [0080]    The upper end of the hollow pivot axle  2  forms two anti-rotation flats  20  and  20   a  (a key) and a threaded hole  22  that mates with matching anti rotation flats pocket (slot) and hole formed through the cap  6 . When the key is fitted into the slot of the cap and the cap is drawn tight with the use of fastener  14  (such as a socket screw) the entire spray head is pulled together to form water and air tight internal passageways that permit the flow of compressed air and water from the boom of a snow tower to and out of the nozzles even when the rotating body  3  is rotated to different positions. The cap  6  and base  1  remain in fixed relationship to each other and the rotating body can be rotated to desired positions as described more fully hereinafter. 
         [0081]    In the embodiment shown in the Figures eight ports  35 , are provided in the rotating body in which the six nozzles and two throttling inserts are fixed such as by screwing them into the ports. When the head is assembled the hollow interior chambers of the rotating body, in conjunction with the common air channel  33  of the pivot tube (axle)  2  form an air chamber  25  that communicates with the interior of the nucleating nozzle  4 . Compressed air enters the air chamber  25  through at least one port  28  formed in the pivot tube that communicates with air inlet tube  27 . 
         [0082]    A water chamber  26  is formed in the interior of the rotating body  3  that communicates with the throttling insets  41  and  41   a  nozzle through water passageways  42  that communicate with orifice  23  formed in the throttle inserts (see  FIG. 7 ). The water chamber  26  also communicates directly with the water nozzles  12  and  12   a . The connection to nozzle  12   a  and  12   a ′ are through water passageways  42  connecting the lower water chamber  26  with the upper water chamber  26   a . The water chamber  26  communicates with, respectively, the water nozzles  12  and to the nucleating nozzles  4  and  4   a  through the throttling inserts  41  and  41   a . The air chamber  33  communicates the nucleating nozzles  4  and  4   a  in a manner that the air and seed particles are dispersed into the atmosphere. In the Figures the high velocity air communicate from chamber  33  through passageways to atomizing chambers  24  and  24   a  and then into the nozzle  4  and  4   a  carrying with the water that had been atomized by the throttling nozzles  41  and  41   a.    
         [0083]    A plug  5  is fitted snugly into the upper portion of the interior hollow upper portion of the rotatable body  3 . The top face  5   a  of the plug mates with the bottom face  6   a  of the cap  6  and its circumference mates with the interior circumference of the body  3  to form a fluid tight, but still rotatable, seal. The circumference surface of the plug may include a grove and o-ring sealing mechanism  8  to assist in forming a fluid tight seal with the interior upper hollow portion of the rotatable body  3  while still permitting the body  3  to rotate around the axle,  2 . 
         [0084]    The plug  5  is secured to the cap  6  with fasteners, such as screws  13  and  13   a . Socket screws or other types of fasteners can be employed. In this embodiment the plug is shown as a separate part. In practice other means can be used to form the fluid tight but rotatable seal between the cap and the rotatable body. For example the cap  6  may be formed with an integral portion extending down from the bottom of the cap that would serve the same function as does the plug  5 . 
         [0085]    The diameter of cap  6  is greater than the diameter of the plug  5  and the diameter of the cap generally matches, but dose not have to, the outside diameter of the rotatable body  3 . An outer ring  36  of the lower face of the cap that equals the difference between the diameter of the plug and the diameter of the cap mates with the upper ring shaped face  37  of the upper portion of the body  3 . If desired the two faces can be provided with mechanisms that control the degree of rotation of the rotatable body  3 . For example the upper face  37  can be provide with indents that match with a spring loaded ball detent pin that is fixed in the cap  6 . Standard spring loaded devices known in the art such a spring encapsulated in a threaded body containing a pin or ball can be employed. For ease of replacement these are generally threaded devices that can be mated with a threaded bore in the cap. The rotating body,  3 , can be rotated to fixed positions that relate to the number of detents formed in the surface of the ring of the body  3 . A detent insert can be used in the rim of the body or detents can be machined into the surface thereof. In the embodiment shown in the Figures a circular groove  18 ,  FIG. 4 , is formed in the lower face of the cap  6  and a pin  16  is fixed into the upper face of the body  3 . The groove and pin act together to restrict the degree of rotation of the body  3 . In other embodiments the spray head parts can be fitted together with the o-rings providing sufficient friction to the hold the rotating body  3  in fixed positions. 
         [0086]    In the embodiment shown in the Figures the base  1 , the rotating body  3 , the pivot tube (axle)  2 , the cap  6 , and the plug  5 , are all aligned on a common symmetrical axis. 
         [0087]    The specific embodiment described shows the use of a pivot tube (axle) to permit rotation of the rotating body  3 . Other means such a ball and socket and the like means may be used to permit the functional rotation of the rotating portion. 
         [0088]    Reference may be made to  FIGS. 8 ,  9  and  10  in describing the method of the present invention. In practice the invention is fixed to a standard snow tower (as shown in  FIG. 6 ) and placed over a ski trail. Depending on wind direction the head is rotated so that the nozzles face generally downwind. Seed crystals are formed by injecting compressed air and water into the head through the tower connections to make snow that is deposited on the trail.