Patent Application
20090294547
The present disclosure relates to machines, and particularly to snow machines used to make snow. More particularly, the present disclosure relates to a snow machine that produces snow at higher atmospheric temperatures. In order for a ski resort to attract skiers, sufficient snow must be provided on the slopes for skiing. The longer the ski resort can maintain a snow base on the slopes, the longer the ski resort can operate.
In traditional ski resorts, artificial snow has been produced using snow machines when sufficient snow can not be obtained under natural conditions. The snow machines mix water, which is cooled to about −3° Celsius, with compressed air and the mixture is blown from nozzles into the air. The compressed air and water mixture turns into snow before the water droplets reach the ground. Atomized water droplets from the nozzles of the snow machine can produce a large amount of snow quickly using the evaporation heat from the water due to the frigid air.
Snow production becomes difficult or impossible when the outside air temperature is from about −3° C. to about 0° C. and above, because the crystallization speed of the water droplets is slow due to the higher atmospheric temperatures. Several snow making methods have been proposed for producing snow. Japanese patent application H08-110137 teaches the use liquid nitrogen to make snow crystals. The cost of using liquid nitrogen is high and this technique has not been commercialized. Japanese patent applications JP2001-201221, H10-339532, H03-501404, and H11-172940 teach snow surface maintenance methods that use dry air. However, these methods are used to form snow crystals naturally in enclosed spaces, and include the method of controlling the temperature and humidity in an enclosed space. These methods are not designed to be used outdoors.
Japanese patent application H10-339532 teaches a method used to maintain the humidity and temperature in enclosed spaces and a method used to secure the height when water mist is sprayed and changed into the snow according to the time of mist falling. Again, this system is not designed to be used outdoors.
Japanese patent application JP2001-304732 teaches the method of outdoor snow making and requires the air to have a temperature of 0° C. or less and the dew point 0° C. or less. However, according to this condition, the relative humidity is 100% and water evaporation can not be utilized. Artificial snow making can not be expected using this method.
Hence, according to the description of JP2001-304732, the temperature near the upper limit of the air to be acted on is not clear. Actually, as to snow making enabling conditions, outside air conditions have top priority, and is the main factor for snow making. Unless the wet bulb temperature is 0° C. or less, even snow that fell naturally would melt. In reverse, unless the temperature is less than 0° C., water droplets would not make snow naturally.
Japanese Patent application JP06-257917 teaches directly injecting into two fluid nozzles on the air side of the snow machine. In this case, right before spouting from the fluid nozzles, the air mixes with water and the cold energy of the air is absorbed into the water. Hence, the advantage of low temperature and low humidity air can not be utilized at all.
In recent years, it is rare to find a ski resort in Japan that has an outside temperature of −3° C. or less in February. During this period the snow machines are inoperable and it is not possible to obtain snow accumulation of sufficient volume for skiing. In order to solve this problem, in recent years, even if the outdoor temperature is high, snow making is done using the ice making machine that can produce snow. However, when ice making machines are used, power consumption is large reducing resort profits.
According to the present disclosure, a snow machine includes a water supply and one or more nozzles that are used to create water droplets used to make snow when the outside temperature is not only 0° C. or less, but also up to +5° C.
In illustrative embodiments, the snow making machine includes a snow accelerator that is provided with an air compressor for compressing air, and equipment that adsorbs moisture from the compressed air. The snow accelerator also includes cooling equipment which cools the low humidity air. The snow accelerator further includes an air expansion valve that subjects the compressed air to decompression expansion and an air nozzle that discharges the modified compressed air from the air expansion valve into the atmosphere adjacent a water jet nozzle of the snow machine. The snow system is controlled by a control device. The modified compressed air, which has an absolute humidity of about 0.1 grams per cubic meter (g/m3) or less and a temperature of about −20° C. or less, is ejected from a spray nozzle against the water mist being sprayed from the water nozzles of the snow machine to cause the water mist to change into snow ice crystals, making snow.
Additional features of the disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the disclosure as presently perceived.
The detailed description particularly refers to the accompanying figures in which:
A snow accelerator machine 100 is shown coupled to snow machine in the illustrative embodiment of
The air adjusted by the disclosed method will be hereinafter called modified air.
The compressed air used for snow making by a snow machine 104 is produced by the following method. An air compressor 1 takes in the air from an air intake 2. In this example, the atmospheric air has a relative humidity of 80%, a temperature of 0° C., and an absolute humidity 3.89 g/m3. When the air is compressed from its suction temperature around 0° C. and 0.7 Mpa, the air temperature climbs to about 30° C. The temperature of the compressed air at this stage is too high, and it is not likely to assist in making snow.
Thus, the air leaving air compressor 1 is cooled to the temperature of about +5° C. by cooling device 4. At this temperature the moisture in the air is not frozen by cooling device 4. Water separation filter 3 discharges the saturated water from the compressed air. The discharged air goes through the high pressure air line 12 from a flange 5 and is connected to the air connection 9 of snow gun 102, as shown in
Water used by the snow gun 102 is stored in a storage tank 6 or is supplied by city water lines, as shown, for example, in
Snow accelerator 100 is added to snow gun 102 and is used to enhance the snow making abilities of snow gun 102 when less than ideal weather conditions exist (−3° C. or greater), as shown in
When the pressurized air is dehumidified using this method, the absolute humidity at the frost point temperature is about 0.1 g/m3 at about −40° C. If the temperature is higher than −40° C., frost is not generated in the air stream or related conduits. Thus, if the air is cooled by a freezer 62 to −30° C., frost or ice is not generated inside the air passages.
Air at tee 20 of
The dehumidified air passes through a check valve 52 and a filter 57, and is cooled inside the air exchanging device 59, as shown in
The cooling method used is a general cooling method. Hence, no details are particularly described about the cooling equipment, cooling medium and the like. The cooling system used is required to reach a temperature from about −35° C. to about −40° C. to sufficiently cool the dehumidified air. Here, the dry air from the dehumidifier was cooled to −30° C. which is higher than the frost point temperature and forms the modified or adjusted air for accelerating the production of snow.
If the incoming air volume from the compression air inlet 50 is larger than the capacity of the adsorption dehumidifier 54, then the desired specified dehumidification is not obtained. Hence in order to adjust for this condition a user, after looking at the indicator value of the air meter 65, adjusts the flow volume of the compressed air by use of an air expansion valve 63, as shown, for example, in
In conducting tests, the test snow making machines were run for 8 hours with modified compressed air having an absolute humidity of about 0.1 g/m3 at about −40° C. After running the equipment for eight hours it was confirmed that no frosting was generated in the flow route of the cooling air, and no blocking of the lines was generated.
Ring shaped adjusted air supply duct 33 is fitted with spout nozzles 34, which are arranged in a radial pattern. As to the nozzle design, spray angles and fan width of the spray should be taken into account so that maximum contact is made with the spray water. Modified compressed air is coupled to air supply duct by use of connector 30.
During the test, spray water 14 was sprayed from the snow gun 31 under high pressure, and the adjusted air 35 exiting the nozzles 34 was subjected to an adiabatic expansion and surrounded the spray water 14, as shown, for example, in
If one observes the spout 14 of the snow machine, as the water spray 14 moves forward, the air layers of the modified compressed air 35 and the spray flow 14 get mixed. Placing a hand about 5 to 6 meters in front of the snow machine during the test, it was confirmed that the water droplets were changed into about 1 mm ice particles. The structure of a fan-type snow machine is illustrated in
In a fan-type snow machine, a fan 44 is placed inside the cylinder shaped wind channel housing 48, and air is blown forward through the wind channel housing 48 by fan blade 44, similar to a hair drier. In this illustration, shaft 46 of fan 44 is rotated by a motor and drive belt or is powered by a hydraulic motor. As to its structure, a pressurized water duct 49 positioned in a ring shape is positioned in front of the wind channel housing 48. Water is ejected from a plurality of nozzles 40 into the air passing from the wind channel housing 48. The feed water supply from pressurized water pump 8 is connected to hose 42 to feed the nozzles similar to the method shown in
The modified compressed air supply 64 of
The run conditions at the time of testing were as follows; inlet water pressure was approximately 1.5 Mpa, water volume was about 200 L/min, outside air temperature was about +3.6° C., wet bulb temperature was about −2.1° C., and relative humidity was about 18.5% RH. The modified air from nozzle 47 was blown inside of the wind channel 48. Modified air contacted the misty water that was ejected from nozzles 40 of the pressurized water duct 49 and the entire volume of water was converted into snow.
It is difficult to visually measure at what distance from the wind channel outlet, the snow was formed, and however it can be confirmed that snow was formed by the snow fall on the ground. When the modified air supply from nozzle 47 stopped, the water from nozzles 40 immediately changed to misty rain.
A large ski resort is equipped with a snow making system, as shown, for example, in
The snow making test was started under the following conditions: outside temperature +3.6° C., wet bulb temperature −2.1° C., and humidity 18.5% RH. The test snow gun arrangement with the snow accelerator that was used during the test is shown in
Under these test conditions, initially, when the sprayed misty water dropped to the ground about 8˜15 meters in front of the machine, misty rain was produced but turned to snow. When this condition prevailed, the modified air had a temperature of about −32° C., absolute humidity of about 0.1 g/m3 and a frost point temperature −45° C. was made by the snow making acceleration machine of
At this time in the test, air temperature was −60° C. or less at the outlet of the expansion valve 63 and the absolute humidity dropped to 0.014 g/m3.
Almost at the same time as spraying water from the nozzles, it was confirmed that the water droplets were changing into snow within a few meters of the fan outlet. Even during this snow making, the natural outdoor conditions kept changing all the time. Even after six hours had passed and the air temperature climbed to +3.5° C. and the wet bulb temperature was −1.2° C., snow making continued. The change to snow decreased in the vicinity of an outside temperature of +4.3° C. and a wet bulb temperature of 0° C. Under these conditions, the water volume was decreased and an adjustment was made. In this test, by making an air adjustment, the snow making in the +0° C. temperature area was recognized to occur. And during test runs, no blocking or frosting occurred in any of the supply lines.
As a comparison example, the adjusted air of temperature 40° C., absolute humidity 0.1 g/m3, frost point temperature −45° C. from the air produced by the snow accelerator in
As part of the test, the adjusted/modified air was directly connected to the air connector 9 of the snow gun main body 11, and mixed with the water within the gun, the cold energy in the air is absorbed into the water as a latent heat. This arrangement did not contribute to improving the snow making capability of the snow machine. It was understood from the test that the water temperature exiting the nozzles dropped a little.
Using a large air dehumidifier 70 for multiple cooling systems 71 allows for the air dehumidifier to be installed at the lower part of the ski slope. The cooling systems 71 can be positioned at 500 meters and 600 meters on top of the mountain, for example, near the snow machine main body. With this arrangement a plural number of the air cooling devices 71 can be installed near the snow machine main body. Placing the cooling devices 71 at the site of the snow machine reduces the size of the cooling equipment needed, decreasing individual equipment costs and construction costs.
Minimalizing the equipment size simplifies the installation work of the equipment, which is greatly desired. If the dehumidification process of the dehumidifier is positioned at the foot of the mountain, the duct line 72 does not freeze because the air passing through the line is dehumidified. Since the equipment is used in the winter time, a longer the duct line 72 is beneficial because the line is cooled by the outside conditions, requiring a smaller cooling device 71.
While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
