US20090294547A1

US20090294547A1 - Snow making apparatus and method

Info

Publication number: US20090294547A1
Application number: US12/129,160
Authority: US
Inventors: Takumi Ichinomiya; Tomoaki Akiyama
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-05-29
Filing date: 2008-05-29
Publication date: 2009-12-03

Abstract

A snow making apparatus that allows for the production of snow when the outdoor air temperature is from about −3° Celsius or colder to about +5° Celsius. The snow making apparatus includes a snow machine that includes one or more water nozzles that spray a water mist into the air. The snow making apparatus also includes a snow accelerator that includes an air compressor, a dehumidifier to remove moisture from the compressed air and a cooling system to cool the compressed dehumidified air. The cooled air is passed through an expansion valve and the modified compressed air is directed through a nozzle positioned to lie near the water nozzles. The modified compressed air has a absolute humidity of about 0.02 g/m³or less and a temperature of about −50° Celsius or less. The water mist and modified compressed air are combined, causing the water mist to turn into snow.

Description

BACKGROUND

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.

SUMMARY

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.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figures in which:

FIG. 1A is a flow diagram showing the entire structure of a gun type snow machine;

FIG. 1B is a elevational view of the snow nozzle of FIG. 1A showing a high pressure water inlet and a high pressure air inlet;

FIG. 2 is an flow diagram showing a snow accelerator combined with a gun type snow machine;

FIG. 3A is a side elevational view showing the snow accelerator nozzle combined with a gun type snow machine;

FIG. 3B is a front elevational view of the snow accelerator nozzle combined with the water nozzle of the snow machine;

FIG. 4 is an elevational view showing the snow accelerator nozzle added to a fan-type snow machine;

FIG. 5 is a flow diagram of the snow accelerator; and

FIG. 6 is flow diagram of a separation type of a snow accelerator.

DETAILED DESCRIPTION

A snow accelerator machine 100 is shown coupled to snow machine in the illustrative embodiment of FIG. 2. The present disclosure offers a method and apparatus in which water vapor is evaporated from spray water droplets, cooled and crystallized by use of low temperature air. The conditioned air has a very low temperature and an extremely low humidity. In terms of numeric values, the conditioned air has a temperature of about −40° C., absolute humidity of about 0.02 g/m3, and the frost point temperature of about −55° C. or less.
The air adjusted by the disclosed method will be hereinafter called modified air. FIG. 1A shows a snow gun 102 which is a type of a snow machine 13. The snow gun 102 includes a plurality of nozzles 11 that spray water droplets to form a mist. Nozzles 11 are coupled to a high pressure air supply line 12 and a high pressure water supply line 13. Air and water from the supply lines 12, 13 spout from the nozzles 11 of the snow gun 102. By using snow accelerator 100 and spraying the modified air from nozzles 34, atomized water droplets are frozen at a faster rate, and snow crystals and ice crystals are produced.
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 FIG. 1B.
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 FIG. 1A. The water exits storage tank 6 and passes through filter 7. Filtered water is pressurized to about 1.5 Mpa by a water pump 8, and passes through high pressure water hose 13. High pressure water hose 13 is connected to water connection 10 of nozzle 104. Snow making by a traditional snow machines is done using the method described so far. However, if the outside temperature increased to −3° C. or greater, snow making is not possible.
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 FIGS. 2 and 5. Snow accelerator 100 includes an air dehumidifier 54 that comprises two vessels 54(a), 54(b). The first vessel 54(a) adsorbs moisture to dry the air, and the second vessel 54(b) performs the drying process in the event the first vessel 54(a) is offline. Valving is used to selective control the airflow through the vessels 54(a) and 54(b). The air dehumidifier 54 uses moisture absorbent zeolite 56 to absorb the moisture from the air. While zeolite is preferred, other multi-porous moisture absorbent materials can also be used including active alumina, silica gel, molecular sieves, active carbon, which all act as absorbents.
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 FIG. 2 passes from a coupler 50 through a dust filter 67, a drain water filter 51, and a check valve 52, as shown in FIG. 5. Air passing through check valve 52 passes through a four way valve 53, and then passes through the first dehumidifying tank 54(a) equipped with zeolite 56. The air exiting dehumidified tank 54 it is dehumidified. Dehumidified tanks 54(a) and 54(b) repeat the dehumidifying process and renewal process alternatively so that one of the two systems is always on line. In general, 15% of dry air created by the dehumidifier tanks is used for renewal. The dehumidified air used for renewal is discharged from a discharge coupler 66, as shown in FIG. 5.
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 FIG. 5. With regard to the method used for cooling the dehumidified air, the cooling medium that was sent out from the freezer 62 is subjected to a throttle expansion by the expansion valve 58. Air from the air expansion valve 58 enters cooling duct coil 60, and is cooled to an evaporation temperature from about −35° C. to about −40° C. Heat exchanged cooling medium returns and passes through duct 61 and returns to a freezer 62, to form a cooling cycle.
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 FIG. 5. Air expansion valve 63 allows a user to attain the specified air volume. By making these adjustments, the air under pressure expands in volume, and causes dehumidification and the temperature to drop.
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. FIG. 3A shows the conditions in which a snow accelerator 100 is added to the snow machine 104 that is run in the condition in FIG. 1A. The air nozzle equipment 33, 34 is coupled to the snow gun 31 by use of mounted stay 32. The modified compressed air is sprayed from nozzles 34. However, an adiabatic expansion is not performed by these nozzles.
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 FIG. 3A. Modified compressed air 35 exiting the nozzles 34 had a reduction of moisture by 1/7. The absolute humidity of the air exiting the nozzles 34 became 0.014 g/m3 and the temperature was −60° C. at the nozzle outlet.
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 FIG. 4.
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 FIG. 1A.
The modified compressed air supply 64 of FIG. 5 made by the snow accelerator 108 is connected to line 47(a), as shown in FIG. 4. Modified compressed air exits nozzle 47 and is blown into the suction 45 created by fan blade 44. The dehumidified low temperature air does not cause frost on the fan 44 or the internal wind channel 48, and, during testing, continuous snow making acceleration effect was obtained.
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 FIG. 1A-1B. The system includes an air compressor 1, water supply equipment having a pressurized pump 8 and a nozzle 11. During the test, the snow accelerator 100 was added to existing snow making equipment and it was found that by using the snow accelerator 100, snow could be made in conditions where snow making was not previously possible.
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 FIG. 2. FIG. 2 shows the combination of the nozzles that spout the modified air to the snow gun. The air compressor 1 was pressurizing air to a pressure of about 0.7 Mpa and a flow rate of about 17 m3/min and the water pump 8 pressurized the water to pressure of about 1.3 Mpa with a flow rate of about 200 L/min, and a temperature of about +3.5° C. Connection hose 13 from the pump was connected to the snow gun 11 at connection 10 and the facility was run.
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 FIG. 5. The air supply pressure was adjusted by air expansion valve 63. The main part of the expansion valve 63 is the needle valve, which is used to control the rate of air through the valve.
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. FIG. 3 is the expanded detail of Part M of FIG. 2 with the modified air coupled to connection 9 of the gun and the water supply coupled to connection 10. The adjusted air passes through the air ring 33 having a plurality of nozzles 34 attached thereto. Nozzle positions are adjusted so that collision of the modified air occurs with the spray water.
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 FIG. 5 was connected directly to the snow gun air coupling 9 in FIG. 1 from a coupler 64, and snow making run was attempted. The test was run to see what kind of effects would be produced compared with the first and second tests. As a result, when the machine was run at the outside air −2° C., no crystallization was seen in the misty water.
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.
FIG. 6 shows an example of a separation type snow accelerator 100 for long distance use. The snow accelerator 100 of FIG. 5 shows a separation line 68 that has the air dehumidifier on the right side of the figure, and the air cooling equipment on the left side of the figure. In FIG. 6, one air dehumidifier 70 is used for a plural number of cooling systems 71.
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.

Claims

1. A method for making snow in a non-sheltered outdoor environment where the outdoor air temperature is from about −3° Celsius to about +5° Celsius and has a wet bulb temperature of no more than about 0° Celsius, the method comprising the steps of:

ejecting pressurized water through a first nozzle to produce water droplets;

producing conditioned compressed air that has an absolute humidity of no more than about 0.1 g/m³and a temperature of no more than about −20° Celsius;

passing the conditioned compressed air through an air expansion valve to form modified compressed air having an absolute humidity of no more than about 0.02 g/m³and a temperature of no more than about −50° Celsius;

ejecting the modified compressed air from a second nozzle that is positioned to lie near the first nozzle;

wherein the water droplets ejected from the first nozzle encounter the modified compressed air ejected from the second nozzle and turn into ice crystals to form snow.

2. The method for making snow of claim 1, wherein the conditioned compressed air is formed by use of an air compressor to pressurize the air and a dehumidifier system to remove moisture from the pressurized air.

3. The method for making snow of claim 2, wherein the dehumidifier system uses multi-porous moisture absorbent materials to dehumidify the pressurized air.

4. The method for making snow of claim 2, wherein the dehumidifier system uses two independent dehumidifiers and valving to allow for selective control of the pressurized air through the dehumidifiers.

5. The method for making snow of claim 4, wherein the conditioned compressed air is cooled by use of a cooling system.

6. The method for making snow of claim 5, wherein the compressor and dehumidifier system are positioned to lie near the cooling system.

7. The method for making snow of claim 5, wherein the compressor and dehumidifier system are separated from the cooling system.

8. The method for making snow of claim 7, wherein the cooling system is positioned to lie near the point where the snow is produced and is in fluid communication with the air compressor and dehumidifier system.

9. A snow making machine that can produce snow when the outdoor air temperature is from about −3° Celsius to about +5° Celsius and has a wet bulb temperature of no more than about 0° Celsius, the snow making machine comprising:

a pressurized water supply;

at least one water nozzle coupled to the pressurized water supply, the water nozzle adapted to spray water in fine droplets to form a mist;

a snow accelerator comprising

an air compressor for compressing air;

a dehumidifier system for dehumidifying the air compressed by the air compressor;

a cooling system for cooling the air dehumidified by the dehumidifier system;

an air nozzle that is adapted to expel air that has been modified by the air compressor, dehumidifier system and cooling system, the air nozzle positioned to lie near the water supply nozzle to allow the modified air to mix with the mist to form snow.

10. The snow making machine of claim 9, wherein the snow accelerator includes an expansion valve for expanding the air cooled by the cooling system.

11. The snow making machine of claim 9, wherein the air exiting the air nozzle has an absolute humidity of no more than about 0.02 g/m³and a temperature of no more than about −50° Celsius.

12. The snow making machine of claim 9, wherein the dehumidifier system uses multi-porous moisture absorbent materials to dehumidify the pressurized air.

13. The snow making machine of claim 12, wherein the dehumidifier system uses two independent dehumidifiers and valving to allow for selective control of the pressurized air through the dehumidifiers.

14. The snow making machine of claim 9, further including a fan blade to create moving air.

15. The snow making machine of claim 14, wherein the fan blade is positioned between the water nozzle and the air nozzle.

16. The snow making machine of claim 14, wherein the fan blade is positioned to lie near the water nozzle.

17. The snow making machine of claim 16, further including a housing, wherein the fan blade is positioned within the housing.

18. The snow making machine of claim 9, wherein the snow making machine includes a plurality of water nozzles coupled to a water manifold.

19. A snow making machine that can produce snow when the outdoor air temperature is from about −3° Celsius to about +5° Celsius and has a wet bulb temperature of about 0° Celsius or less, the snow making machine comprising:

a pressurized water supply;

a tubular housing;

a fan positioned within the tubular housing and adapted to create a flow of air through the tubular housing;

a plurality of water nozzle coupled to the pressurized water supply, the water nozzles positioned around the diameter of the tubular housing and adapted to spray water in fine droplets to form a mist;

an air compressor for compressing air;

a cooling system for cooling the air dehumidified by the dehumidifier system;

an air nozzle that is adapted to expel air that has been modified by the air compressor, dehumidifier system and cooling system, the air nozzle positioned to lie near the water supply nozzles to allow the modified air to mix with the mist to form snow.

20. The snow making machine of claim 19, wherein the air exiting the air nozzle has an absolute humidity of about 0.02 g/m³or less and a temperature of about −50° Celsius or less.