US3464625A - Method and means for making snow - Google Patents

Description

P 2, 1969 o. CARLSSON 3,464,625

METHOD AND MEANS FOR MAKING SNOW Filed Jan. 4, 1966 2 Sheets-Sheet 1 INVENTOR OSTEN CARLSSON B ERIC Y. MUNSON Sept. 2, 1969 Filed Jan. 4, 1966 2 Sheets-Sheet 2 OSTEN CARLSSON INVENTOR.

BY ERIC Y. MUNSON United States Patent METHOD AND MEANS FOR MAKIYG SNOW Osten Carlsson, Nacka, Sweden, assignor to Atlas Copco Aktiebolag, Nacka, Sweden, a corporation of Sweden Filed Jan. 4, 1966, Ser. No. 518,705

Claims priority, application Sweden, Jan. 22, 1965,

841/ 65 Int. Cl. A01g /00,- E01h 13/00; B05b 7/12 U.S. 'Cl. 239-2 2 Claims ABSTRACT OF THE DISCLOSURE A means for making snow from atomized water into the ambient atmosphere having a freezing point lower than water, the means including a housing in which water and compressed air are directed, the housing including a tube containing an elongated conically widening expansion nozzle having a throat at its inner end. There is an annular gap provided in the tube around the throat for delivering compressed air thereto to create a jet of water particles for ejection from the nozzle under simultaneous expansion and cooling in the nozzle of the air creating and ejecting the particles. A pump is provided in the water conduit leading to the nozzle and means is provided for forcing water under pressure into the throat. A valve is provided in the water conduit for regulating pressure of the water to control the effective area of the gap offered to the compressed air in the housing, the intake tube having an internal taper converging toward the throat so that the throat acts as a water-driven suction jet pump preventing flooding of the air line when the air pressure therein is insufficient.

The invention relates to a method and means for making snow. Snow has been made artificially before, more particularly by the delivery of compressed air and water into a mixing chamber, in which a jet of water particles was formed by the compressed air and ejected thereby out into the ambient cold atmosphere. For effective operation one had to use a set of exchangeable nozzles at the transition between the mixing chamber and the ambient air for purposes of throttling the outlet in order to adapt it and the jet to temperature variations in the ambient atmosphere. This adaptation was also supported by influencing the incoming water pressure as well as the compressed air pressure and thus the handling of the system became quite cumbersome. The throttling nozzles also resisted outward flow of water at insufficient air pressure which resulted in flooding and subsequent freezing of air lines and sources on occasions when the latter by some reason became inoperative. It has been proposed to use simple atomizing nozzles of jet pump type for purposes of ejecting the jet directly into the atmosphere but this proposition has not resulted in any practically useful apparatus.

It is the main object of the invention to increase in connection with snow making the effectiveness of the structure and system therefor and to simplify their use. Another object of the invention is to prevent flooding and subsequent freezing of the air system during insufiicient air pressure. These objects are attained by the adaptation of the jet pump principle for water atomization and ejection in a practical realizable and effective form.

The invention will be described more in detail by the aid of the enclosed drawings in which FIG. 1 is a side view showing the snow making means according to the invention mounted on a stand and coupled to form a system with lines for the delivery of water and compressed air. FIG. 2 is a longitudinal section through the snow making means in FIG. 1.

In FIG. 1 the snowmaking means includes a housing 10 which is connected to a ball joint 12 by means of a shaft portion 11. By a clamping nut 13 actuatable by a handle 14, the ball joint 12 and shaft portion 11 can be locked in variable angular position relative to a mounting 15 on a tripod stand 16. The stand 16 includes legs 17 by which it can be placed on the ground. One of the legs 17 may be provided with a telescoping extension 18 which by means of a screw 19 permits longitudinal adjustment of said leg 17 so that the mounting 15 can be levelled without regard to inclination of the ground.

The housing in FIG. 2 carries a laterally directed connecting tube 20 to which a compressed air hose or line 21 is connected. At the rear portion of the housing 10 is disposed a water intake tube 22 which is connected to a water supply hose 23.

Coaxially with the intake tube 22 there is provided in the housing 10 an elongated expansion nozzle 24, which by means of threads 25 can be adjusted axially with respect to the intake tube 22 so that an annular gap 26, through which the compressed air enters into the mixing zone or passage 27 of the housing 10, can be adjusted as to its width. The compressed air is conducted to the annular gap 26 from the connecting tube 20 via a lateral bore 28 in the housing 10 to an inner air chamber 30 therein surrounding the water intake tube 22. The air chamber 30 is sealed by means of an O-ring 31 placed around the expansion nozzle 24. In front of the mixing zone 27 which is formed by a throat provided at the inner end of the nozzle 24, the nozzle 24 widens conically forming an elongated expansion channel 32. The water intake tube 22 has an internal taper converging towards the minimum cross-sectional internal area of the throat or passage 27.

The shaft portion 11 of the ball joint 12 is provided with a threaded portion 33 by which it is connected to the outer end of the connecting tube 20.

As shown in FIG. 1 the housing 10 is used together with a suitable compressor plant, indicated by the arrow 35, from which compressed air, if desired via an air cooled aftercooler 36, is delivered to a main air line 37 substantially at ambient temperature. To the main air line are connected one or more housings 10 by means of the compressed air hoses 21 which are opened or closed by means of air valves 38. In the system there is finally included a Water source 40 from which water is pumped under pressure by means of a pump 41 to a main line 42. The Water supply hoses 23 of the housings 10 are connected to this main line 42 via adjustable throttling valves 43.

During operation of the system with a group of housings 10 in action, the air lines 21 are adjusted for full air supply to the air chamber 30 of the housing 10 by fully opening the air valves 38. Thereupon one sets via the water valves 43 a suitable incoming water pressure in the water intake tube 22 with respect to the actual air temperature. When said temperature lies below the freezing point of water, one searches by adjustment of the water valve 43 for the vest valve setting for forming ice crystals of snow character in and outwardly of the expansion nozzle 24, taking into account the actual outer temperature. By means of the ball joint 12 and the clamping nut 13 one adjusts the desired throwing angle for the nozzles 24 so that the ice crystals are ejected into the atmosphere falling on the ground at the desired spot and the system is left working until the desired snow depth is reached. Thereupon the stand 16 is moved or the angle of adjustment is changed at the ball joint 12 so that adjacent ground portions can be covered eventually by the desired snow depth. By means of the water valve 43 one adjusts the water quantity forced into the water intake tube 22. Hereby the effective area of the annular gap 26 around the passage 27 offered to the compressed air a in chamber 30 is influenced so that the ratio between the incoming air quantity and the incoming water quantity to the zone 27 may be influenced effectively and adapted to variations of the outer temperature solely through manipulation of the water valve 43. Effective snow formation normally takes place when the quantity of the supplied free compressed air in litres per minutes relates to the quantity of incoming water in litres per minute in a ratio lying between 400:1 and 50:1. For best results this ratio is changed through manipulation of the water valve 43 so that snow formation is at its best with respect to the actual outer temperature. The water valve 43 can also be regulated for providing a basic layer of comparatively wet snow of high carrying capacity at the beginning of the snow coating process which basic layer freezes on the ground, whereupon the work .is finished by spraying a dry layer of cover snow suitable for skiing. By increasing the proposition of air to water, by means of the valve 43 the housing can if necessary, be operated under the cooling of ice so that the waterparticles in the expansion channel 32 proper are leaving the nozzle 24 as ice crystals having the character of snow.

At insuflicient pressure in the air chamber 30, the tapered intake tube 22 directs a compact stream of water towards and through the minimum cross sectional area of the throat 27, whereby the latter acts as a water driven suction jet pump preventing flooding of the air system. The free flow of water through housing 10 also keeps the water mass under movement which is also apt to minimize freezing of the system.

I claim: 1. A method for making snow out of water which is atomized by the aid of compressed air and ejected as a jet of discrete particles into the ambient atmosphere when the latter has a temperature lower than the freezing point of water, said atomization being performed by the aid of and in the mixing zone of a jet pump coupled to receive compressed air and water for said atomization, said method comprising the combined steps of:

leading said jet from said mixing zone out into the atmosphere via an expansion nozzle extending from said mixing zone along a substantial portion of the axial length of said jet under continuous expansion cooling in said nozzle of the air mass carrying said j delivering the compressed air to the mixing zone under substantially constant pressure, delivering the water to the mixing zone under pressure in a manner to create suction in the compressed air-receiving part of said jet pump when the air pressure therein is insufficient, and

varying the delivery pressure of the water for purposes of variably choking the air delivery to the mixing zone thereby changing the ratio between the air quantity and the Water quantity used up per unit of 55 time for the formation, ejection and cooling of said particles.

2. Means for making snow out of water which is atomized by the aid of compressed air and is ejected as a jet of discrete particles into the ambient atmosphere when the latter has a temperature lower than the freezing point of water, said means comprising in combination:

a housing, a water intake tube in said housing,

water conduit means connected to said housing for supplying water to said tube, an air chamber in said housing around said tube,

an air line connected to said housing for supplying compressed air to said air chamber,

an elongated conically widening expansion nozzle connected to said housing coaxially in front of said intake tube,

a throat at the inner end of said nozzle, said throat longitudinally overlaps said water intake tube to form an annular gap between said tube and said noozle around the inside surface of said throat for delivering compressed air thereto to create said jet of water particles therein and out through said nozzle under simultaneous expansion and cooling in the nozzle of the air creating and ejecting the particles,

a pump in said water conduit, means for forcing water under pressure by way of the tube into the throat,

a regulating valve in the water conduit means for regulating said pressure in said tube for purpose of regulating by the water passing the gap the effective area of said gap offered to the compressed air in said chamber, and

said intake tube having an internal tapered conversion toward said throat whereby said throat acts as a water driven suction jet pump preventing flooding of the air line when the air pressure therein is insufficient.

References Cited UNITED STATES PATENTS 1,835,603 12/1931 Kincaid 23092 X 501,164 7/1893 Roberts 239416.5 1,962,547 6/1934 Zerk 248-181 X 2,571,069 10/1951 Shearman 2392 X 3,212,217 10/1965 Furgason 239424 X 3,279,703 10/ 1966 Steltz et al 239424 X 3,301,485 1/1967 Tropeano et al. 2392 FOREIGN PATENTS 765,446 3/1934 France. 869,312 11/1941 France.

M. HENSON WOOD, Primary Examiner M. Y. MAR, Assistant Examiner US. Cl. X.R.

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