CA2276016C - Snow gun for making artificial snow - Google Patents

Abstract

In a snow gun, each of air and water are discharged through V jet nozzles in the form of generally flat and V-shaped jets or sprays. The nozzles are spacially positioned and angled so that the air jet intersects the water spray along a line of intersection where they are of equal width. This provides efficient atomization of the water with the result that snow can be made at milder freezing temperature. In another aspect, a flanged connection, having dual sealed openings for passage therethrough of pressurized air and water streams, is provided to join the gun and its supporting tower. In another aspect, the snow gun has a plurality of associated intersecting water sprays and air jets which are oriented to produce non-converging plumes.

Description

2 The present invention relates to method and apparatus for making artificial

3 snow.

4 BACKGROUND OF THE INVENTION
6 In general, artificial snow-making involves atomizing a spray of water with a jet 7 of air to create a plume of very fine water droplets which nucleate and form snow as 8 the plume drops to earth under freezing temperature conditions.
9 The present invention is a modification of a known snow-making system patented and commercialized by Herman K. Dupre.
11 In United States Patent No. 3,706,414, issued December 19, 1972) Dupre 12 taught bringing pressurized air and water through separate flowlines to the bases of 13 hillside towers positioned along a ski trail. The air and water were introduced at 14 controlled rates into a mixing chamber positioned at the foot of each tower. The mixture then flowed upwardly through a conduit forming the tower and was 16 discharged through nozzles. Inherent in this system were the following features:
17 ~ some atomization or reduction in water droplet size due to ~18 mixing with air;
19 ~ rapid cooling of the water when the pressurized air was released into the freezing atmosphere and it expanded;
21 ~ the provision of dwell time as the plume fell to earth from an 22 elevated starting point; and 23 ~ some control over the airlwater ratio, with a view to optimizing it.

1 In a subsequent United States Patent, No. 3,822,825 issued July 9, 1974, 2 Dupre taught bringing the water and air separately up the tower in inner and outer, 3 concentric, spaced apart conduits. The air flowed through the inner conduit 4 passageway and the water through the outer annular passageway formed between the conduits. As a result) the water stream functioned to insulate the air stream.
6 There is moisture in the air and it will condense and freeze to form "rime ice" if the 7 atmospheric temperature is low enough and the air stream becomes chilled 8 sufficiently. In another aspect taught, the air was delivered to a tee and released into 9 the atmosphere through a pair of diametrically opposed orifices. These orifices were holes drilled through the wall of the outer conduit, to communicate with the bore of 11 the tee. Dupre taught that the air outlet should be flush with the outer surface of the 12 outer conduit, to avoid cooling of the air while passing through the orifice with 13 consequent formation of rime ice, which could block the orifice. Dupre further taught 14 discharging the water through a nozzle angled at 45° relative to the long axis of the conduit and having a shaped orifice adapted to deliver a substantially flat and V-16 shaped spray. His air orifice was positioned just above the water nozzle and was 17 angled at about 90° relative to the long axis of the conduit. The term "associated ,18 pair" is used herein to denote a pair of outlets arranged so that the air jet and water 19 spray which they produce intersect with the result that the air atomizes the water and a nucleated plume is produced. The air orifice was positioned to discharge its jet into 21 the throat of the water spray. In another feature, Dupre taught mounting diametrically 22 opposed associated pairs of air orifices and water nozzles, each pair being at a 23 common elevation. This arrangement is referred to as providing a "bank" of 1 associated pairs of air orifices and a bank of water nozzles. Inherent in this design 2 were the following concepts:
3 ~ bringing the air and water through separate conduits to the 4 discharge elevation;
~ using the water stream to insulate the air stream until it was 6 discharged to the atmosphere;
7 ~ associating the air orifice and water nozzle in a spatial 8 arrangement such that the air jet would converge with and 9 contact the water spray, to cause atomization; and ~ utilizing a bank of air and water outlets.
11 In a still more recent patent, United States No. 5,004,151 issued April 2, 1991, 12 Dupre addressed the need to increase snow production capacity. A discrete snow 13 gun was attached to the upper end of a conduit tower secured to a vertical post. The 14 snow gun had an associated pair of water and air outlets, comprising a water nozzle and an air orifice. A second water nozzle was inwardly spaced along the gun from 16 the outer water nozzle of the associated pair. The second water nozzle was inclined 17 at a more acute angle than the first water nozzle, so that the water spray of the (18 second nozzle would converge into and contact the plume produced by the 19 associated pair. In this way, the available single jet of air was used to atomize the two sprays of water.

1 The Dupre system has won commercial success. The commercial version 2 incorporates the features described above. It can be described more specifically as 3 follows:
4 ~ a snow gun is mounted on a boom or tower having universal movement;
6 ~ the gun has two banks of V jet water nozzles spaced along the 7 lorig axis of the gun;
8 ~ a single bank of air orifices is associated with the outer water 9 bank;
~ the inner bank of water nozzles directs its sprays into the 11 nucleated sprays of the outer bank; and 12 ~ coaxial water and air conduits form the body of the gun and 13 provide an annular outer passageway for supplying pressurized 14 water to the two banks of water nozzles and an insulated inner passageway for supplying pressurized air to the single bank of 16 air orifices.
17 While the Dupre system has been an admirable success, there are still certain ~18 shortcomings which could be improved upon. More particularly:
19 ~ the Dupre system is not capable of producing quality snow at freezing temperatures milder than -6°C using a water volume 21 . that would be commercially viable. The literature indicates that 22 the system can only operate at -6°C with a low humidity of about 23 60%. There are many ski areas that have a significant number

5 1 of days during the season when the temperature is milder than -2 6°C. There is therefore a need to develop a system which can 3 operate at milder freezing temperatures;
4 ~ it is always desirable to increase the snow-making capacity of the snow gun;

6 ~ there is a need to provide a snow gun which can be used

7 without air when the temperature is cold; and

8 ~ there is a need to provide a flanged snow gun that is

9 disconnectable from the tower, for easy removal to permit service to the snow gun and to permit replacement with a snow 11 gun having upgraded components.
12 It is an objective of the present invention to provide a snow gun which satisfies 13 these needs.
14 By way of further background, it is pointed out that the V jet nozzles used in the art are classified by the designations 5020, 5040 and 5060. A 5020 nozzle 16 produces a flat, V-shaped spray having an angularity of about 50°
and discharges 2 17 U.S. gpm of water, when operated at 40 psi. A 5040 nozzle produces a similar spray 18 at 4 U. S. gpm at 40 psi. And the 5060 nozzle produces a similar spray at 6 U. S. gpm 19 at 40 psi. If the pressure is increased, all of the nozzles will deliver more water at a wider anale.

2 In one feature of the present invention, an air nozzle which produces a 3 substantially flat and V-shaped air jet is associated with a water nozzle which 4 produces a substantially flat and V-shaped water spray, in the context of a snow gun, the two nozzles being spacially arranged or coupled so that the air jet and water 6 spray converge and intersect along a line where their widths are substantially equal.
7 The phrase "coupled pair" is used to denote an air nozzle and water nozzle pair as 8 described in the previous sentence. A coupled pair is a specific embodiment of an 9 associated pair.
When a snow gun having a coupled pair of air and water outlets, as described 11 is operated, a remarkably efficient and complete atomization of the water into very 12 fine droplets is achieved. This degree of atomization has enabled the gun to 13 produce snow at -1'/Z C at 85% humidity.
14 In another feature, a plurality of banks of associated pairs of air and water outlets are spaced along the length of a snow gun. The associated pairs are oriented 16 so that the plumes which they produce do not significantly converge and intersect.
17 For example, the water nozzles of one bank can be similarly angled relative to those (18 of the next bank so that the plumes travel substantially in parallel. By implementing 19 this feature, efficient and complete nucleation of multiple water sprays is obtained while increasing the snow-making capacity of the gun relative to the prior art.

1 The air nozzle preferably should be embedded in the wall structure forming 2 the air and water conduits of the snow gun, to minimize the formation of rime ice.
3 To provide more than one bank of embedded air nozzles has required the 4 development of a unique conduit structure and fabrication process. This has been achieved and is described hereunder.
6 As a result, it is now possible to provide in a snow gun multiple coupled pairs 7 of air and water outlets along the length of the gun, each involving V jet nozzles for 8 both air and water. This has meant that the snow-making capacity of the gun can be 9 increased by using a plurality of banks of coupled pairs and each V-shaped water spray is individually atomized by its own V-shaped air jet. The nozzles of the water 11 banks are angled so that their produced plumes are non-converging; thus one water 12 nozzle bank does not significantly increase the water droplet size of another.
13 By providing air and water outlets that each incorporate V jet nozzles, one can 14 now provide a 5020 nozzle in one outlet and a 5040 nozzle in the other outlet. One then has the option of supplying each of water or air to either the 5020 nozzle or the 16 5040 nozzle, by changing over the fluid supply lines at the base of the tower. Thus, 17 in cold weather when the air/water ratio can be low, one can supply the water through ,18 the 5040 nozzle and the air through the 5020 nozzle, with high snow output. In 19 milder weather, when the air/water ratio needs to be higher, one can supply the water through the 5020 nozzle and the air through the 5040 no?~le - the snow output is 21 diminished but the increased atomization due to higher energy input results in finer 22 water droplets being produced; these finer droplets have a better chance of forming 23 snow at the mild conditions.

1 If desired, at cold temperatures the air can be shut right off and water sprayed 2 through the 5020 nozzle will make snow at an adequate rate without the cost of air 3 compression and without coping with air nozzle freeze up problems. At very cold 4 temperatures, both nozzles can be supplied with water alone.
In summary so far then, the attributes of a system incorporating features of the 6 invention can include:
7 ~ improved atomization) which leads to finer droplet size and the 8 ability to nucleate and form snow at freezing temperatures 9 milder than -6°C;
~ more complete atomization, as the entire width of the water 11 spray preferably is contacted by the air jet;
12 ~ increased snow-making capacity, as more water banks can now 13 be incorporated into a single snow gun and their sprays can be 14 independently nucleated;
~ versatility, in that nozzles of different capacity can be used in a 16 coupled pair and the nature of the fluid discharge of these 17 nozzles can be switched from ground; and ~18 ~ the option to terminate air supply during cold weather 19 conditions.

1 Broadly stated, in one aspect the invention is embodied in a snow gun for 2 making artificial snow, comprising: an inner conduit having a wall forming a first 3 passageway, extending longitudinally of the gun) for delivering a stream of 4 pressurized air; an outer conduit having a wall combining with the inner conduit to form a second passageway, also extending longitudinally of the gun, for delivering a 6 stream of pressurized water; the first passageway extending through the second 7 passageway; a water nozzle connected with the outer conduit and communicating 8 with the second passageway for the discharge of water therefrom, said water nozzle 9 having an orifice operative to produce a substantially flat and V-shaped water spray;
an air nozzle connected with the inner conduit and communicating with the first 11 passageway for the discharge of air therefrom, said air nozzle having an orifice 12 operative to produce a substantially flat and V-shaped air jet; the air nozzle being 13 associated with the water nozzle as a coupled pair so that the water spray and the air 14 jet produced converge and intersect along a line where their widths are substantially equal.
16 The foregoing paragraph states the snow gun in the context of the way that it 17 will be operated for at least part of the time - that is, with air passing through the core .18 passageway and water through the outer passageway. However, as previously 19 outlined, it is contemplated to be within the scope of the invention that the streams can be re~r~rs~d or only water alone will be flowed through both passageways.

1 In still another aspect, the invention comprises providing a flanged connection 2 connecting the lower end of the gun to the upper end of the tower, said connection 3 forming dual sealed openings for connecting the air and water passageways of the 4 tower and gun, so that the streams may pass through the connection without leakage.
6 Broadly stated, in another aspect the invention is embodied in a flanged 7 connection for use in joining a snow gun, having a central passageway for conveying 8 pressurized air and an outwardly spaced passageway for conveying pressurized 9 water, and a tower, having similar inner and outer passageways for air and water, comprising: a tower flange, having a flat face and forming central and outwardly 11 spaced first openings, for connection with the tower so that the first openings register 12 with the tower passageways; a gun flange, having a flat face and forming central and 13 outwardly spaced second openings, for connection with the gun so that the second 14 openings register with the gun passageways; and a plate, having a side edge, for positioning between the tower and gun flanges, the plate having first and second 16 faces and forming central and outwardly spaced third openings for connecting the first 17 and second openings, each of the first and second faces having a first land between 18 the central opening and the outwardly spaced opening and a second land between 19 the outwardly spaced opening and the side edge of the plate, said first land forming a first O-ring groove surrounding the plate's central opening and said second land 21 tormir-g a s;:ccnd O-ring ~~cove cc~. centricvuith the firs: O-ring groove.

1 In another aspect, the invention is embodied in a method for making snow at 2 freezing temperatures, comprising: supplying water under pressure to a water nozzle 3 forming part of a snow gun elevated above ground and discharging the water from 4 the nozzle in the form of a substantially flat and V-shaped spray;
simultaneously supplying air under pressure to an air nozzle forming part of the snow gun and 6 discharging the air from the nozzle in the form of a substantially flat and V-shaped jet;
7 and directing the nozzles so that the spray and jet converge and intersect along a line 8 where their widths are substantially equal.
9 In still another aspect, the invention involves orienting associated pairs of air and water outlets so that their plumes are non-converging. Broadly stated, the 11 invention comprises a snow gun for making artificial snow comprising: an inner 12 conduit having a wall forming an air passageway, extending longitudinally of the gun, 13 for delivering a stream of pressurized air; an outer conduit having a wall combining 14 with the inner conduit to form an annular water passageway, also extending longitudinally of the gun, for delivering a stream of pressurized water; the air 16 passageway extends through the water passageway; and said gun has a plurality of 17 longitudinally spaced apart associated pairs of air and water outlets respectively (18 communicating with the air passageway and water passageway, for delivering 19 intersecting air jets and water sprays and producing plumes of atomized water; the water outlets being oriented so that the plumes produced when the gun is in 21 operation are non-converging.

1 In still another aspect, the invention is embodied in a method for making snow 2 at freezing temperature, comprising: supplying water under pressure to a plurality of 3 water nozzles distributed longitudinally along a snow gun elevated above ground and 4 discharging the water from the nozzles in the form of substantially flat and V-shaped sprays; simultaneously supplying air under pressure to a plurality of air outlets, each 6 air outlet being associated with a water nozzle to form an associated pair, and 7 discharging the air from the nozzles in the form of jets; and directing the nozzles so 8 that each associated spray and jet converge and intersect and the plumes produced 9 by the coupled pairs are non-converging.

12 Figure 1 is a perspective view showing a snow gun mounted on the end of a 13 tower;
14 Figure 2 is a side elevation, partly in section, showing the base, boom and lift assembly of the tower;
16 Figure 3 is a cross-sectional side view of the snow gun;
17 Figure 4 is a top view, sectioned along the line A-A of Figure 3, showing the .18 intersecting, flat, V-shaped air jet and water spray of a coupled pairing of nozzles;
19 Figure 5 is a plan view of a thick-walled ring, sectioned along the line B-B of Figure 3;
21 Figure 6 is an expanded, partly sectional side view of the outer coupled banks 22 of air and water nozzles of a snow gun having a blanked end;
23 Figure 7 is a side sectional view showing the nozzled end cap of Figure 3;

1 Figure 8 is a side sectional view showing the end cap of Figure 7, taken along 2 a plane at 180° relative to that of Figure 7;
3 Figure 9 is a side sectional view showing the flanged connection joining the 4 snow gun with the tower;
Figures 10A - 10K show the fabrication sequence used in constructing the 6 snow gun with welds;
7 Figure 11 is a sectional side view showing the two bank snow gun used to 8 provide the data of Example I; and 9 Figure 12 is a sectional side view of part of the tower) showing a bleed valve for bleeding water into the air stream 13 Having reference to Figure 1, a snow gun 1 is shown mounted on the upper 14 end of a tower 2 by a flanged connection 3. The tower 2 comprises a boom 4.
The boom 4 is rotatably and pivotally supported by a base 5.
16 The base 5 comprises a mounting pipe 6 and lifting assembly 7. Mounting 17 pipe 6 slides over a post 8 which projects from the ground. The lifting assembly 7 (18 enables raising and lowering of the boom 4 to change the elevation of the gun 1 and 19 to access it.

1 As shown in Figure 2, the lifting assembly 7 comprises a pivot pin 9 connected 2 with the mounting pipe 6 and passing through boom 4. A threaded jacking screw 10 3 is pivotally connected at one end with the pivot pin 9. A collar 11 is mounted on the 4 jacking screw 10, for axial movement therealong. A threaded nut 12 engages the jacking screw 10 and functions to bias the collar 11 therealong. A handwheel 13 is 6 attached to the nut 12 for rotation thereof. Two compression members 14, 15 are 7 pivotally connected at their inner ends to the collar 11. The first compression 8 member 14 is pivotally connected at its outer end to the boom 4 by pivot pin 16 at a 9 point above pivot pin 9. The second compression member 15 is connected at its outer end to the mounting pipe 6 by a pivot pin 17 located below pivot pin 9.
Thus, 11 as the collar 11 is advanced along the jacking screw 10 toward pivot pin 9, 12 compression members 14, 15 approach co-linear alignment and raise the boom 4.
13 This arrangement provides significant mechanical advantage and minimizes 14 the height of the base 5. The minimal height enables a single operator to lift the mounting pipe 6 upwardly to clear the post 8 for un-mounting and transportation of 16 the assembly to another site.
17 The tower 2 comprises inner and outer, co-extensive, concentric tubes 18, 19.
~18 The inner tube 18 forms an internal passageway 20. An annular passageway 21 is 19 formed between the tubes 18, 19. The inner tube 18 can be connected by a quick-connect coupling (not shown) with an air hose 22 for the supply of pressurized or 21 compressed air to the inner passageway 20. The outer tube 19 can be connected by 22 a quick-connect coupling (not shown) with a water hose 23 for the supply of 23 pressurized water to the annular passageway 21.

1 As shown in Figure 3, the snow gun 1. also comprises inner and outer, 2 substantially co-extensive and concentric tubes 24, 25 forming an inner passageway 3 26 and outer annular passageway 27. The inner passageway 26 thus extends 4 through the outer annular passageway 27 and is substantially co-extensive therewith.
The tower and snow gun inner passageways 20, 26 are connected, as shown, as 6 are the annular passageways 21, 27. (The inner passageways 20, 26 are hereafter 7 referred to as the air passageways 20, 26 and the annular passageways 21, 27 are 8 referred to as the water passageways 21, 27. ) 9 The tower 2 is connected to the snow gun 1 by the flanged connection 3 having dual openings connecting the air passageways 20, 26 and water 11 passageways 21, 27.
12 The flanged connection 3 is designed to resist the high pressure differential 13 between the water passageway (typically at 700 psi) and the air passageway 14 (typically at 110 psi) and prevent leakage therebetween. Having reference to Figure 9, the tower 2 is provided with a flat-faced (or non-grooved) tower flange 28 forming 16 bolt openings 29, water passageway opening means 30 and air passageway opening 17 31. The snow gun 1 is provided with a flat-faced gun flange 32 forming bolt openings .18 33, water passageway opening means 34 and an air passageway opening 35. A
19 plate 36 is provided between the tower and gun flanges 28, 32. The plate 36 also forms bolt openings 37, water passageway opening means 38 and an air 21 passageway opening 39, positioned to register with the corresponding openings and 22 opening means of the tower and gun flanges, to provide continuity of the water and 23 air passageways. Inner and outer concentric grooves 40, 41 are formed in the 1 annular lands 200, 201 of the top and bottom faces of the plate 36, for receiving O-2 rings 42 for sealing the water and air passageways. The flanged connection 3 is 3 completed by bolts 81 and nuts 80 securing together tower flange 28, plate 36 and 4 gun flange 32.
Having reference to Figure 3, the snow gun's inner tube 24 comprises, from its 6 inner end outward, a series of sequentially repeated units 90, (see Figure 10C) joined 7 end to end. Each unit 90 comprises a relatively thin-walled tube segment 43 joined to 8 a relatively thick-walled ring 44.
9 Each thick-walled ring 44 (see Figure 5) forms a pair of radial, internally threaded openings 45 for receiving V-jet air nozzles 46. When screw-threaded into 11 the openings 45, the air nozzles 46 are generally diametrically aligned and are each 12 fully embedded or recessed in the wall of the ring 44. The ring 44 further forms an 13 axial central opening 70 which forms part of the air passageway 26 and a plurality of 14 relatively small, axial openings 47 which form part of the water passageway 27. The radial openings 45 and the air nozzles 46 contained therein communicate with the 16 central opening 70, which forms part of the air passageway 26.
17 The snow gun's outer tube 25 comprises a series of sequentially repeated ~18 outer units 48 (see Figures 3, 10K). The innermost outer unit 48 joins the gun flange 19 32 and the innermost thick-walled ring 44. The remaining outer units segments 48 join adjacent pairs of thick-walled rings 44. Each outer unit 48 comprises a tube 92 21 and a tubular section formed of "doors" 60a/b, as described below.

1 Broadly stated, the inner and outer units 90, 48 combine to form a wall 2 structure in which the air nozzles 46 are embedded and are insulated by the water 3 moving through the structure.
4 Each outer unit 48 forms a pair of generally diametrically opposed openings 49 into which is welded an angularly directed, tubular dowel 50. Each dowel 50 is 6 internally threaded. A V jet water nozzle 51 is screwed into each dowel 50.
7 The dowels 50 are parallel so that the produced atomized plumes 52 do not 8 converge or intersect.
9 At its outer end, the snow gun 2 is closed by a cap 53. The cap shown in Figures 3, 7 and 8 comprises an axially directed air nozzle 54 and a pair of angularly 11 directed water nozzles 55. Alternatively, the cap 53 may simply blank off the end, as 12 shown in Figure 6.
13 The water and air nozzles 51, 46, 54, 55 all have shaped orifices 56 operative 14 to produce a substantially flat and V-shaped spray or jet. Usually a 5020 air nozzle and 5040 water nozzle is the combination used.
16 An outer air nozzle and inner water nozzle are coupled or relatively positioned 17 as shown in Figure 3, so that the air jet 66 intercepts the water spray 57 along an ,18 imaginary line 58 where the widths of the jet and spray are substantially equal (see 19 Figure 4). A plume 52 of atomized water is produced.
The snow gun is constructed by welding in order to avoid leakage, given that 21 water and air at relatively high pressure are passing therethrough.

1 A novel snow gun structure and welding fabrication sequence has been 2 developed in order to enable the provision of a plurality of thick-walled rings 44.
3 More particularly, as shown in Figures 10a - 10k:
4 ~ a thick-walled ring 44a is welded to a cap 53a at W1;
~ an inner tube segment 43a is seated in the inner end of the ring 6 44a and welded thereto at W2;
7 ~ an outer tube 92a, having water nozzle dowels 50, is slid onto 8 inner tube segment 43a and welded to ring 44a at W3 to 9 produce unit 100;
~ in a separate second sequence, an inner tube segment 43b is 11 welded to the inner end of a thick-walled ring 44b at W4 - an 12 outer tube 92b is slid onto segment 43b and welded thereto at 13 W5 to produce unit 101;
14 ~ in a separate third sequence, an inner tube segment 43c is welded to the inner end of a thick-walled ring 44c at W6 - an 16 outer tube 92c is slid onto segment 43c and welded thereto at 17 W7 to produce unit 102;
(18 ~ unit 101 is slid onto unit 100 so that the inner end of inner tube 19 segment 43a seats in the outer end of thick-walled ring 44b and is welded at W8;
21 ~ similarly, unit 102 is slid onto unit 101 so that the inner end of 22 inner tube segment 43b seats in the outer end of thick-walled 23 ring 44c and is welded at W9;

1 ~ pairs of doors 60a/b and 60b/c are then emplaced to close in 2 the space between outer tube 92a and ring 44b and outer tube 3 92b and ring 44c respectively and are welded at W10 - W17 as 4 shown;
~ a collar 61 is slid onto the inner end of inner tube segment 43c 6 and welded at W18;
7 ~ in a separate fourth sequence, a frusto-conical tube 62 is 8 welded to gun flange 32 at W19 to produce unit 103;
9 ~ unit 103 is then slid onto inner tube segment 43c and is welded to outer tube 92c at W20; and 11 ~ bottom collar 61 is welded to the gun flange 32 to complete the 12 assembly of the snow gun.
13 The snow gun and its operation has been described in the context of air being 14 supplied to the inner conduit passageway 26 and water being supplied to the outer annular passageway 27. This is the mode in which the gun will likely be operated 16 most of the time. However, because V jet nozzles are used in all of the fluid outlets, 17 the air and water supply can be switched to passageway 27 and passageway 26 (18 respectively, when appropriate.
19 As shown in Figures 2 and 12, a cross-mix needle valve 91 can be provided for bleeding a small stream of water (typically about 5 U.S. gpm) from the annular 21 passage 21 into the inner tube passageway 20, for melting rime ice formed therein, 22 when desirable. It has been found desirable to wet the air stream when temperatures 23 drop below -8°C (17°F).

1 An example is now given to report on . a test in which a snow gun in 2 accordance with the invention was operated to produce snow at freezing 3 temperatures milder than -6°C.
4 More particularly, a snow gun in accordance with Figure 11 and having the dimensions set forth in Table I was built and tested.

7 ~ gun length I = 2.5 feet;
8 ~ outer tube: 2" O.D. Schedule 80 aluminium pipe;
9 ~ inner tube: 1-1/4" O.D. aluminum tubing having an I.D. of 1';
~ thick-walled ring having 1/4" O.D. water openings, a 1" central air 1 " opening and 1/4" NPT nozzle connections;
12 ~ air nozzles - 5020;
13 ~ air nozzle angle - 90° to gun axis;
14 ~ water nozzles - 5020;
~ angle of first bank of water nozzles - 45°;
16 ~ angle of second bank of water nozzles - 45°;
17 ~ distance a between first and second bank - 8' ;
~18 ~ distance b between the center of each dowel opening and the center of 19 each air nozzle - 2-1/2".
When tested at the following conditions: -1.5°C, 85% humidity, 40 U.S. gpm 21 at 600 psig, 100 cfm air at 100 psi; the gun produced good base snow.
22 The scope of protection to be accorded the invention is now set forth in the 23 following claims.

Claims (2)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A flanged connection for use in joining a snow gun, having a central passageway for conveying pressurized air and an outwardly spaced passageway for conveying pressurized water, and a tower, having similar inner and outer passageways for air and water, comprising:
a tower flange, having a flat face and forming central and outwardly spaced first openings, for connection with the tower so that the first openings register with the tower passageways;
a gun flange, having a flat face and forming central and outwardly spaced second openings, for connection with the gun so that the second openings register with the gun passageways; and a plate, having a side edge, for positioning between the tower and gun flanges, the plate having first and second faces and forming central and outwardly spaced third openings for connecting the first and second openings, each of the first and second faces having a first land between the central opening and the outwardly spaced opening and a second land between the outwardly spaced opening and the side edge of the plate, said first land forming a first O-ring groove surrounding the plate's central opening and said second land forming a second O-ring groove concentric with the first O-ring groove.

2. The flanged connection as set forth in claim 1 wherein:
the outwardly spaced first, second and third openings are annular and concentric with the central first, second and third openings respectively.