Note: Descriptions are shown in the official language in which they were submitted.
CA 022~8444 1999-01-13
FIELD OF THE INVENTION
2 The present invention relates to method and apparatus for making
3 artificial snow.
BACKGROUND OF THE INVENTION
6 In general, artificial snow-making involves atomizing a spray of water
7 with a jet of air to create a plume of very fine water droplets which nucleate and form
8 snow as the plume drops to earth under freezing tennperature 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,
12 Dupre taught bringing pressurized air and water through separate flowlines to the
13 bases of hillside towers positioned along a ski trail. The air and water were
14 introduced at 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
16 was discharged through nozles. 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 air/water ratio, with a view to opli",i~ing it.
CA 022~8444 1999-01-13
In a subsequent United States Patent, No. 3,822,825 issued July 9,
2 1974, Dupre taught bringing the water and air separately up the tower in inner and
3 outer, concentric, spaced apart conduits. The air Flowed through the inner conduit
4 passageway and the water through the outer annular p~ss~geway formed between
5 the conduits. As a result, the water stream functioned to insulate the air stream.
6 There i.s 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
10 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 bloch the orifice. Dupre further taught
14 discharging the water through a nozle angled at 45~ relative to the long axis of the
15 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 nozle 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
20 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 nozles, each pair being at a
23 common elevation. This a~ ~ dnge" ~ent is referred to as providing a "bank" of
CA 022~8444 1999-01-13
associated pairs of air orifices and a bank of water nozles. 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 discl ,a, yed to the al" ,osphere;
7 ~ associating the air orifice and water nozle in a spatial
8 arrangement such that the air jet would converge with and
g contact the water spray, to cause atomization; and
~ utilizing a bank of air and water outlets.
11In a still more recent patent, United ';tates No. 5,004,151 issued April
122, 1991, Dupre addressed the need to increase snow production capacity. A discrete
13 snow gun was attached to the upper end of a conduit tower secured to a vertical post.
14 The snow gun had an associated pair of water and air outlets, comprising a water
15 nozle and an air orifice. A second water nozle Wc3S inwardly spaced along the gun
16 from the outer water nozle of the associated pair. The second water nozle was
17 inclined at a more acute angle than the first water nozle, so that the water spray of
18 the second nozle would converge into and conltact the plume produced by the
19 associated pair. In this way, the available single jet of air was used to atomize the
20 two sprays of water.
CA 022;i8444 1999-01-13
The Dupre system has won commercial sllccess. The commercial
2 version incorporates the features described above. It can be described more
3 specifically as follows:
4 ~ a snow gun is mounted on a boom or tower having universal
movement;
6 ~ the gun has two banks of Vjel: water nozles spaced along the
7 long axis of the gun;
8 ~ a single bank of air orifices ici associated with the outer water
g 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 and13 provide an annular outer passageway for supplying pressurized
14 water to the two banks of water nozles and an insulated inner
p~ss~geway 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
18 certain 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 ~~C with a low humidity of about
23 60%. There are many ski areas that have a significant number
CA 022~8444 1999-01-13
of days during the season when the temperature is milder than -
2 6~C. There is therefore a neeld to develop a system which can
3 operate at milder freezing temperatures;
4 ~ it is always desirable to increase the snow-making capacily of
the snow gun;
6 ~ there is a need to provide a snow gun which can be used
7 without air when the temperahlre 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 componlents.
12 It is an objective of the present invention to provide a snow gun which
13 satisfies these needs.
14 By way of further background, it is pointed out that the Vjet nozles
used in the art are classified by the designations 5020, 5040 and 5060. A 5020
16 nozle produces a flat, V-shaped spray having an angularity of about 50~ and
17 discharges 2 U.S. gpm of water, when operated at 40 psi. A 5040 nozle produces a
18 similar spray at 4 U.S. gpm at 40 psi. And the 5060 nozle produces a similar spray
19 at 6 U.S gpm at 40 psi. If the pressure is increased, all of the nozles will deliver
20 more water at a wider angle.
CA 022~8444 l999-0l-l3
SUMMARY OF THE INVE.NTION
2 In one feature of the present invention, an air nozle which produces a
3 substantially flat and V-shaped air jet is associated with a water nozle which
4 produces a substantially flat and V-shaped water spray, in the context of a snow gun,
the two nozles being spacially arranged or coupled so that the air jet and water6 spray converge and intersect along a line where the!ir widths are substantially equal.
7 The phrase "coupled pair" is used to denote an air nozle and water nozle 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
11 described is operated, a remarkably efficient and complete alorilk~Lion of the water
12 into very fine droplets is achieved. This degree of atomization has enabled the gun
13 to produce snow at -1 1/2~C at 85% humidity.
14 In another feature, a plurality of banks of associated pairs of air and
15 water outlets are spaced along the length of a snow gun. The ~.ssoci~ted pairs are
16 oriented so that the plumes which they produce clo not significantly converge and
17 intersect. For example, the water nozles of one bank can be similarly angled
18 relative to those of the next bank so that the plumes travel substantially in parallel.
19 By implementing this feature, efficient and complete nucleation of multiple water
20 sprays is obtained while increasing the snow-making capacity of the gun relative to
21 the prior art.
-
CA 022~8444 1999-01-13
The air nozle preferably should be embedded in the wall structure
2 forming the air and water conduits of the snow gun, to minimize the formation of rime
3 ice.
4 To provide more than one bank of embedded air nozles has required
the development of a unique conduit structure and ra~ric~lion prucess. This has
6 been achieved and is described hereunder.
7 As a result, it is now possible to provicle in a snow gun multiple coupled
8 pairs of air and water outlets along the length of the gun, each involving Vjet nozles
9 for both air and water. This has meant that the snow-making capacity of the gun can
10 be increased by using a plurality of banks of coupled pairs and each V-shaped water
11 spray is individually atomized by its own V-shaped air jet. The nozles of the water
12 banks are angled so that their produced plumes are non~onverging; thus one water
13 nozle bank does not significantly increase the wate!r droplet size of another.
14 By providing air and water outlets that each incorporate Vjet nozles,
15 one can now provide a 5020 nozle in one outlet and a 5040 nozle in the other
16 outlet. One then has the option of supplying each of water or air to either the 5020
17 nozle or the 5040 nozle, by changing over the fluid supply lines at the base of the
18 tower. Thus, in cold weather when the air/water ratio can be low, one can supply the
19 water through the 5040 nozle and the air through the 5020 nozle, with high snow
20 output. In milder weather, when the air/water ral:io needs to be higher, one can
21 supply the water through the 5020 nozle and the air through the 5040 nozle - the
22 snow output is diminished but the increased atomization due to higher energy input
23 results in finer water droplets being produced; these finer droplets have a better
CA 022~8444 1999-01-13
chance of forming snow at the mild conditions.
2 If desired, at cold temperatures the air can be shut right off and water
3 sprayed through the 5020 nozle will make snow at an adequate rate without the cost
4 of air compression and without coping with air nozzle freeze up problems. At very
cold temperatures, both nozles can be supplied with water alone.
6 In summary so far then, the attributes of a system incor~.ordling
7 features of the invention can include:
8 ~ improved atomization, which leads to finer droplet size and the
9 ability to nucleate and form snow at freezing temperatures
milder than ~~C;
11 ~ more con,,~'ete atomization, clS the entire width of the water
12 spray preferably is contacted by the air jet;
13 ~ increased snow-making capacity, as more water banks can now
14 be incorporated into a single snow gun and their sprays can be
independently nucleated;
16 ~ versatility, in that nozles of different capacity can be used in a
17 coupled pair and the nature of the fluid discharge of these
18 nozles can be switched from ground; and
19 ~ the option to terminate air supply during cold weather
conditions.
CA 022;i8444 1999-01-13
Broadly stated, in one aspect the invention is embodied in a snow gun
2 for 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 pAssage~vay, also extending longitudinally of the gun, for delivering a
6 stream of pressurized water; the first p~.ssagewa~y extending through the second
7 passageway; a water nozle connected with the outer conduit and communicating
8 with the second pass~geway for the discharge of water therer~ùn1, said water nozle
9 having an orifice operative to produce a substantially flat and V-shaped water spray;
an air nozle connected with the inner conduit and communicating with the first
11 p~ss~geway for the discharge of air ll,erer,ur", ciaid air nozle having an orifice
12 operative to produce a substantially flat and V-shaped air jet; the air nozle being
13 associated with the water nozle as a coupled pair cio that the water spray and the air
14 jet produced converge and intersect along a line where their widths are substantially
1 5 equal.
16 The foregoing paray,aph states the SllOW gun in the context of the way
17 that it will be operated for at least part of the time - that is, with air passing through
18 the core p~ss~geway and water through the outer passageway. However, as
19 previously outlined, it is conte",plated to be within the scope of the invention that the
streams can be reversed or only water alone will be flowed through both
21 passageways.
22 In still another aspect, the invention cc,n,~ rises providing a flanged
23 connection connecting the lower end of the gun to the upper end of the tower, said
.. _ ,
CA 022~8444 1999-01-13
connection for" ,ing dual sealed openings for connecting the air and water
2 passageways of the tower and gun, so that the streams may pass through the
3 connection without leakage.
4 In another aspect, the invention is embodied in a method for makingsnow at freezing temperatures, cor~ rising: supplying water under pressure to a
6 water nozle forming part of a snow gun elevated above ground and disch2l"~ ng the
7 water from the nozle in the form of a substantially flat and V-shaped spray;
8 simultaneously supplying air under pressure to an alir nozle forming part of the snow
9 gun and discharging the air from the nozle in the Form of a substantially flat and V-
10 shaped jet; and directing the nozles so that the spray and jet converge and intersect
11 along a line where their widths are substantially equal.
12 In still another aspect, the invention involves orienting associated pairs
13 of air and water outlets so that their plumes are non-converging. Broadly stated, the
14 invention comprises a snow gun for making artifiicial snow comprising: an inner
15 conduit having a wall forming an air passageway, extending longitudinally of the gun,
16 for delivering a stream of pressurized air; an outer conduit having a wall combining
17 with the inner conduit to form an annular wal:er p~.ss~geway, also extending
18 longitudinally of the gun, for delivering a strealm of pressurized water; the air
19 passageway extends through the water passageway; and said gun has a plurality of
20 longitudinally spaced apart associated pairs of air and water outlets respectively
21 communicating with the air p~ssageway and water p~.ss~geway, for delivering
22 intersecting air jets and water sprays and producing plumes of atomized water; the
23 water outlets being oriented so that the plumes produced when the gun is in
CA 022~8444 1999-01-13
operation are non-converging.
2 In still another aspect, the invention is embodied in a method for
3 making snow at freezing temperature, comprising: supplying water under pressure to
4 a plurality of water nozles distributed longitudinally along a snow gun elevated
above ground and discharging the water from the nozles in the form of substantially
6 flat and V-shaped sprays; simultaneously supplying air under pressure to a plurality
7 of air outlets, each air outlet being associated with a water nozle to form an
8 associated pair, and discharging the air from the nozles in the form of jets; and
9 directing the nozles so that each associated spray and jet converge and intersect
10 and the plumes produced by the coupled pairs are non-converging.
11 In still another aspect, the invention is concerned with an appa,~tus for
12 making artificial snow co~lp~ising a tower having an upper end and comprising13 tubular, concentric, co-extensive, spaced apart inner and outer conduits forming an
14 inner air p~.ss~geway for delivering a pressurized air stream and an annular outer
15 water p~ss~geway for delivering a pressurized water stream; a snow gun having a
16 lower end and comprising inner and outer conduits forming an inner air p~ss~geway
17 and an annular outer water passageway; a flangecl connection connecting the lower
18 end of the gun to the upper end of the tower, said connection forming a sealed
19 central opening extending therethrough and joining the tower air p~ss~geway with
20 the gun air p~ss~geway and a sealed second opening means extending therell " uugh
21 and joining the tower water passageway with the gun water p~ss~geway, so that the
22 air and water sl,ear"s may pass form the tower through the connection into the gun
23 without leakage; said gun having air and water outlets communicating with the gun's
CA 022~8444 1999-01-13
air and water passageways, respectively, for producing plumes of atomized water.
3 DESCRIPTION OF THE D~WINGS
4 Figure 1 is a perspective view showing a snow gun mounted on the
end of a tower;
6 Figure 2 is a side elevation, partly in section, showing the base, boom
7 and lift assembly of the tower;
8 Figure 3 is a cross-sectional side view of the snow gun;
9 Figure 4 is a top view, sectioned along the line A--A of Figure 3,
showing the intersecting, flat, V-shaped air jet and water spray of a coupled pairing of
1 nozles;
12 Figure 5 is a plan view of a thick-walled ring, sectioned along the line
13 B--B of Figure 3;
14 Figure 6 is an expanded, partly sectional side view of the outer coupled
banks of air and water nozles of a snow gun having a blanked end;
16 Figure 7 is a side sectional view showing the nozled end cap of Figure
17 3;
18 Figure 8 is a side sectional view showing the end cap of Figure 7,
19 taken along a plane at 180~ relative to that of Figure 7;
Figure 9 is a side sectional view showing the flanged connection
21 joining the snow gun with the tower;
13
CA 022~8444 1999-01-13
Figures 1 OA - 1 OK show the fabrication sequence used in constructing
2 the snow gun with welds;
3 Figure 11 is a sectional side view showing the two bank snow gun used
4 to provide the data of Example l; and
Figure 12 is a sectional side view of part of the tower showing a bleed
6 valve for bleeding water into the air stream.
8 DETAILED DESCRIPTION OF THE PREF:ERRED EMBODIMENT
9 Having reference to Figure 1 a snow gun 1 is shown mounted on theupper end of a tower 2 by a flanged connection 3. The tower 2 comprises a boom 4.
11 The boom 4 is rolalably and pivotally supported by a base 5.
12 The base 5 comprises a mounting pipe 6 and lifting assembly 7.
13 Mounting pipe 6 slides over a post 8 which pro;~cts from the ground. The lifting
14 assembly 7 enables raising and lowering of the boom 4 to change the elevation of the
gun 1 and to access it.
16 As shown in Figure 2 the lifting assembly 7 coi"prises a pivot pin 9
17 connected with the mounting pipe 6 and passing through boom 4. A threaded jacking
18 screw 10 is pivotally connected at one end with the pivot pin 9. A collar 11 is
19 mounted on the jacking screw 107 for axial movement therealong. A threaded nut 12
engages the jacking screw 10 and functions to bias the collar 11 therealong. A
21 handwheel 13 is attached to the nut 12 for rotalion thereof. Two cori,pression
22 members 14 15 are pivotally connected at their inner ends to the collar 11. The first
23 compression member 14 is pivotally connected at its outer end to the boom 4 by pivot
14
CA 022~8444 1999-01-13
pin 16 at a point above pivot pin 9 The second compression member 15 is
2 connected at its outer end to the mounting pipe 6 by a pivot pin 17 located below
3 pivot pin 9. Thus, as the collar 11 is advanced along the jacking screw 10 toward
4 pivot pin 9, col"pressio" members 14, 15 approach co-linear alignment and raise the
boom 4.
6 This arrangement provides significant mechanical advanlage and
7 minimizes the height of the base 5. The minimal height enables a single operator to
8 lift the mounting pipe 6 upwardly to clear the post 8 for un-mounting and
9 transportation of the assembly to another site.
The tower 2 comprises inner and outer, co-extensive, co"ce, lll ic tubes
11 18, 19. The inner tube 18 forms an internal p~.ssAgeway 20. An annular
12 passageway 21 is formed between the tubes 18, 19. The inner tube 18 can be
13 connected by a quick-connect coupling (not shown) with an air hose 22 for the supply
14 of pressurized or compressed air to the inner passa!3eway 20. The outer tube 19 can
15 be connected by a quick-connect coupling (not shown) with a water hose 23 for the
16 supply of pressurized water to the annular passageway 21.
17 As shown in Figure 3, the snow gun l also comprises inner and outer,
18 substantially co-extensive and concentric tubes 24, 25 forming an inner p~ss~geway
19 26 and outer annular passageway 27. The inner passageway 26 thus extends
20 through the outer annular p~ssageway 27 and is substantially co-extensive therewith.
21 The tower and snow gun inner p~ss~geways 20, 26 are connected, as shown, as
22 are the annular passageways 21, 27. (The inner p~ss~geways 20, 26 are hereafter
23 referred to as the air passageways 20, 26 and the annular p~ss~geways 21, 27 are
CA 022~8444 1999-01-13
referred to as the water passageways 21 27.)
2 The tower 2 is connected to the snow gun 1 by the flanged connection
3 3 having dual openings connecting the air passageways 20 26 and water
4 p~ss~geways 21 27.
The flanged connection 3 is designed to resist the high pressure
6 differential between the water passageway (typically at 700 psi) and the air
7 passageway (typically at 110 psi) and prevent leakage therebetween. Having
8 reference to Figure 9 the tower 2 is provided with a flat-faced (or non-grooved) tower
9 flange 28 forming bolt openings 29 water passageway opening means 30 and air
10 passageway opening 31. The snow gun 1 is provided with a flat-faced gun flange 32
11 forming bolt openings 33 water p~ss~geway opening means 34 and an air
12 passageway opening 35. ~ plate 36 is provided between the tower and gun flanges
13 28 32. The plate 36 also forms bolt openings 37 water passageway opening means
14 38 and an air p~ss~geway opening 39 positioned to register with the corresponding
15 openings and opening means of the tower and gun flanges to provide continuity of
16 the water and air p~ss~geways. Inner and oute!r conce"~,ic grooves 40 41 are
17 formed in the annular lands 200 201 of the top and bottom faces of the plate 36 for
18 receiving O-rings 42 for sealing the water and air p~ss~geways. The flanged
19 connection 3 is completed by bolts 81 and nuts 80 securing together tower flange 28
20 plate 36 and gun flange 32.
16
CA 022~8444 1999-01-13
Having reference to Figure 3, the snow gun's inner tube 24 comprises,
2 from its inner end outward, a series of sequentially repeated units 90, (see Figure
3 1 OC) joined end to end. Each unit 90 comprises a relatively thin-walled tube segment
4 43 joined to a relatively thick-walled ring 44.
Each thick-walled ring 44 (see Figure 5) forms a pair of radial,
6 internally threaded openings 45 for receiving Vjet air nozles 46. When screw-
7 threaded into the openings 45, the air nozles 46 are generally diametrically aligned
8 and are each fully embedded or recessed in the wall of the ring 44. The ring 44
9 further forms an axial central opening 70 which forms part of the air p~ss~geway 26
and a plurality of relatively small, axial openings 47 which form part of the water
11 p~ss~geway 27. The radial openings 45 and the air nozles 46 contained therein
12 communicate with the central opening 70, which forrns part of the air p~ss~geway 26.
13 The snow gun's outer tube 25 cornprises a series of sequentially
14 repeated outer units 48 (see Figures 3, 10K). The innermost outer unit 48 joins the
gun flange 32 and the innermost thick-walled ring 44. The remaining outer units
16 segments 48 join adjacent pairs of thick-walled rings 44. Each outer unit 4817 comprises a tube 92 and a tubular section forme~d of "doors" 60a/b, as described
1 8 below.
19 Broadly stated, the inner and outer units 90, 48 combine to form a wall
structure in which the air nozles 46 are embedded and are insulated by the water21 moving through the structure.
17
CA 022~8444 1999-01-13
Each outer unit 48 forms a pair of generally diametrically opposed
2 openings 49 into which is welded an angularly directed, tubular dowel 50. Each
3 dowel 50 is internally threaded. A Vjet water nozle 51 is screwed into each dowel
4 50.
The dowels 50 are parallel so that the produced atomized plumes 52
6 do not converge or intersect.
7 At its outer end, the snow gun 2 is closed by a cap 53. The cap shown
8 in Figures 3, 7 and 8 comprises an axially directed air nozle 54 and a pair of
9 angularly directed water nozles 55. Alternatively, the cap 53 may simply blank off
10 the end, as shown in Figure 6.
11 The water and air nozles 51, 46, 54, 55 all have shaped orifices 5612 operative to produce a substantially flat and V-shaped spray or jet. Usually a 5020
13 air nozle and 5040 water nozle is the combination used.
14 An outer air nozle and inner water nozle are coupled or relatively
15 positioned as shown in Figure 3, so that the air jet 66 intercepts the water spray 57
16 along an imaginary line 58 where the widths of the jet and spray are substantially
17 equal (see Figure 4). A plume 52 of atomized water is produced.
18 The snow gun is constructed by welding in order to avoid leakage,
19 given that water and air at relatively high pressure are passing therethrough.
18
CA 022~8444 1999-01-13
A novel snow gun structure and welding fabrication sequence has
2 been 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 waler nozle 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 sequenc,e, an inner tube segment 43b is
11 welded to the inner end of a lthick-walled ring 44b at W4 - an
12 outer tube 92b is slid onto se~3ment 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 seat~i in the outer end of thick-walled
23 ring 44c and is welded at W9;
19
.
CA 022~8444 1999-01-13
~ 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 l:he 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
14 air being supplied to the inner conduit p~.ssAgewa~y 26 and water being supplied to
15 the outer annular passageway 27. This is the mode in which the gun will likely be
16 operated most of the time. However, because Vjet nozles are used in all of the fluid
17 outlets, the air and water supply can be switched to p~ss~geway 27 and passageway
18 26 respectively, when appropriate.
19 As shown in Figures 2 and 12, a cross-mix needle valve 91 can be
20 provided for bleeding a small stream of water (typically about 5 U.S. gpm) from the
21 annular p~.ss~ge 21 into the inner tube passageway 20, for melting rime ice formed
22 therein, when desirable. It has been found desirable to wet the air stream when
23 temperatures drop below-8~C (17~F).
CA 022~8444 1999-01-13
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 accorclance with Figure 11 and having5 the dimensions set forth in Table I was built and tes,ted.
6 TABLE I
7 ~ gun length I = 2.5 feet;
8 ~ outer tube: 2" O.D. Schedule 80 alunninium pipe;
9 ~ inner tube: 1-1/4" O.D. aluminum tubing having an l.D. of 1";
~ thick-walled ring having 1/4" O.D. water openings, a 1" central air
11 opening and 1/4" NPT nozle connections;
12 ~ air nozles - 5020;
13 ~ air nozle angle - 90~ to gun axis;
14 ~ water nozles - 5020;
~ angle of first bank of water nozles - 45~;
16 ~ angle of second bank of water nozles - 45~;
17 ~ distance a between first and second bank - 8";
18 ~ distance b between the center of each dowel opening and the center of19 each air nozle - 2-1/2".
When tested at the following conditions: -1.5~C, 85% humidity, 40 U.S.
21 gpm 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
23 the following claims.
, . . , . , ... _
