SPRAY DEVICE FOR ARTIFICIAL SNOW PRODUCTION AND ITS APPLICATION METHOD

Description

Technical field of the invention

[0001] The present invention generally relates to the field of the manufacture of artificial snow, also called snow.

[0002] It relates more particularly to a spraying device for the production of artificial snow, as well as a method for implementing this spraying device. State of the art

[0003] In the above field, it is known to manufacture artificial snow to place it on downhill or cross-country ski slopes, in order to compensate for the lack of natural snow, or to equip indoor slopes.

[0004] Documents WO 2008 / 056086 A1, FR 2 260 072 A1, WO 95 / 23320 A1, US 4 730 774 A and WO 2006 / 092868 A1 disclose spraying devices for making artificial snow.

[0005] As described in documents FR-2 743 872, WO-9718421, EP-1 123 479, EP-1 386 668 or FR-2 995 391, it is then conventional to install, on at least part of the edges of the ski slopes, devices for spraying water or a mixture of air and water (also called "snow guns"), supplied by pressurized water pipes and pressurized air pipes, to enable the production of this artificial snow.

[0006] Such spraying devices generally comprise a pole fixed in the ground, which conveys, via separate supply conduits, pressurized water and pressurized air to a snowmaking head located at its free end, several meters or even ten meters high.

[0007] These water and air supply pipes are connected to the general water and air pipes which line the runway, and their supply is managed by dedicated valves provided in a box or shelter located at the foot of each pole.

[0008] The snowmaking head often comprises a plurality of spray nozzles whose supply of pressurized water and possibly pressurized air is adjusted by one or more valves, in order to optimize the quantity of artificial snow to be produced depending on the weather conditions.

[0009] There are several spraying techniques, each with their own advantages and limitations, in particular: external air and water mixing systems which use water spraying elements of the nozzle type with a constant opening section, for example known as a “fanjet” (see for example document FR-2 995 391).

[0010] These nozzles consist of full and flat fan type spray nozzles that have fixed flow rates and produce fine to medium droplets (with diameters between 100 and 400µm).

[0011] This type of nozzle draws in ambient air and distributes the droplets in ways suitable for snowmaking. It is then the water pressure that gives the droplets speed, which draws in the ambient air.

[0012] It is possible to modulate the flow rate by adjusting the water pressure, but this is not really of interest because the higher the pressure, the finer the droplets: they freeze more quickly and carry more air with them.

[0013] In practice, the highest available water pressure is used.

[0014] With this technique, it is not possible to adapt the droplet size and flow rate to the air temperature. The best performance at a given temperature is a combination of the exit section and the exit angle of the sprayed water stream. Smaller sections are required at high temperatures, and multiple nozzles are required to achieve the maximum possible flow rate.

[0015] To adapt the flow rate to the temperature, it is therefore necessary to combine different nozzle sizes by using several nozzle stages (see in particular EP-1 123 479); in this case, the optimum in terms of flow rate and drop size, and therefore air entrainment, is only achieved for the first stage alone.

[0016] The different combinations are compromises. external air and water mixing systems which use water spray elements of the variable aperture nozzle type (see EP-1 386 668). Such nozzles consist of thin-walled hollow jet type spray nozzles which have progressive flow rates and produce medium to large droplets (with a diameter between 200 and 500 µm).

[0017] Such systems allow the droplet size and flow rate to be adapted to all temperatures and to remain at the theoretical optimum for snow production over a wide operating range. However, this technique has a limit at high temperatures that has not been possible to date to exceed and therefore does not allow the snow gun to be started at a temperature as high as with a fanjet nozzle. internal air and water mixing systems (see for example FR 2 743 872).

[0018] These nozzles can produce fine droplets, less than 400µm in diameter; but the compressed air consumption in this case is very high, which limits their interest.

[0019] The spraying technique used to equip a site is chosen taking into account the prevailing winds, the width of the slopes, the slopes, etc., knowing in all cases that the lower the temperature, the easier it is to produce quality artificial snow.

[0020] With variable opening section technology (and therefore variable flow), the start-up temperature is generally below -3.5°C to obtain dry snow.

[0021] With other techniques, it is generally possible to produce dry snow from -2°C, however with a reduced flow rate which gives them relative efficiency.

[0022] In order to combine quantity and early start (i.e. obtaining a significant volume of snow at relatively high temperatures), it would be advisable to increase the number of fixed stages on the snowmaking heads (there are snow guns with 6 or 8 stages), but this then results in increasing head complexity with the consequence of increasing the weight and exposure to frost of the devices.

[0023] Therefore, outside of specific favorable conditions, current spray heads do not have optimal efficiency. Presentation of the invention

[0024] In order to overcome the aforementioned drawback of the state of the art, the present invention provides a device according to claim 1.

[0025] Such a spray device structure, comprising different types of spray elements on the same support, makes it possible to combine the advantages of the two technologies and therefore to obtain maximum snow production by starting this production at the highest possible temperature.

[0026] Other non-limiting and advantageous characteristics of the spraying device according to the invention, taken individually or in all technically possible combinations, are as follows: said at least one nozzle with constant opening section consists of a spray nozzle of the full and flat jet type, and said at least one nozzle with variable opening section consists of a spray nozzle of the thin-walled hollow jet type; each of said control valves is associated with its own piloting means; said first and second control valves are each maneuvered in translation by a worm screw controlled in rotation by an actuator, the sequencing of the position of said first and second control valves being carried out by intervening electrically, electronically or by software on the actuators of said worm screws; said at least one nozzle with variable opening section comprises a movable axial throttling member for adjusting said opening section, and the movement of said axial throttling member is controlled by an actuator;the spraying device comprises at least two nozzles with a constant opening section, the opening sections of which are different; the supply of water and air to said nucleating element is carried out independently of said first and second control valves, said support body comprises: (i) a nozzle with a variable opening section, (ii) a plurality of nozzles with a constant opening section, arranged around said nozzle with a variable opening section, and (iii) a plurality of nucleating elements, arranged between said nozzle with a variable opening section and said nozzles with a constant opening section. ;

[0027] By "constant aperture nozzle type water spray element" and "variable aperture nozzle type water spray element" are meant spray elements supplied solely by the pressurised water supply means and therefore adapted to spray only water, in order to produce water droplets capable of producing snow.

[0028] On the other hand, by "element for spraying a mixture of air and water" is meant spraying elements supplied by the means for supplying water under pressure and by the means for supplying air under pressure, constituting an element called a "nucleation element" adapted for seeding a main jet of water droplets making it possible to optimize the transformation of the water droplets of this main jet into snow.

[0029] Such nucleating elements are not suitable in themselves for producing artificial snow; they are different, both in structure and function, from the above-mentioned constant aperture nozzle-type water spraying elements and variable aperture nozzle-type water spraying elements.

[0030] The present invention also relates to a method for implementing a spraying device according to claim 1, for the production of artificial snow, which method consists, taking into account a first temperature threshold S1 and a second temperature threshold S2 greater than S1: (i) actuating in the closed position said first control valve for supplying water to said at least one constant section nozzle and said second control valve for supplying water to said at least one variable section nozzle, above said threshold S2, (ii) actuating in the open position said first control valve and actuating in the closed position said second control valve, between said thresholds S1 and S2, and (iii) actuating in the open position said second control valve and actuating in the closed position said first control valve below said threshold S1; preferably the method consists in overlapping the open positions of said first and second control valves on said threshold S1, or close to said threshold S1; further, taking into account a third temperature threshold S3 lower than S1, the method consists in actuating in the open position said first control valve for supplying water to said at least one constant section nozzle and said second control valve for supplying water to said at least one variable section nozzle, below said threshold S3;according to an alternative embodiment, the method for implementing a spraying device according to claim 1, for the production of artificial snow, consists, taking into account a first temperature threshold S1 and a second temperature threshold S2 greater than S1: (i) actuating in the closed position said first control valve for supplying water to said at least one constant section nozzle and said second control valve for supplying water to said at least one variable section nozzle, above said threshold S2, (ii) actuating in the open position said first control valve and actuating in the closed position said second control valve, between said thresholds S1 and S2, and (iii) actuating in the open position said second control valve and said first control valve, below said threshold S1; the method consists in providing a minimum opening position of said at least one variable opening section nozzle;the method consists in increasing the flow rate of said at least one variable section nozzle with the decrease in temperature, until a maximum flow rate is reached.; Detailed description of the invention

[0031] In addition, various other characteristics of the invention emerge from the appended description given with reference to the drawings which illustrate non-limiting forms of embodiment of the invention and where: [ Fig. 1 ] is a schematic front view of a spraying device according to the invention; [ Fig. 2 ] is a sectional view of the spraying device according to section plane 2-2 of the Figure 1 ; [ Fig. 3 ] is a sectional view of the spraying device according to section plane 3-3 of the Figure 1 ; [ Fig. 4 ] is a sectional view of the spraying device according to section plane 4-4 of the Figure 1 ; [ Fig. 5] is a sectional view of the spraying device according to section plane 5-5 of the Figure 1 ; [ Fig. 6 ] is a sectional view of the spraying device according to section plane 6-6 of the Figure 1 ; [ Fig. 7 ] is a schematic side view of the spraying device illustrated in the figures 1 to 6 ; [ Fig. 8 ] is a sectional view of the spraying device according to section plane 8-8 of the Figure 7 ; [ Fig. 9 ] is a sectional view of the spraying device according to section plane 9-9 of the Figure 7 ; [ Fig. 10 ] is a sectional view of the spraying device according to section plane 10-10 of the Figure 7 . Spraying device

[0032] On the figures 1 to 10 an embodiment of a spraying device 1 for producing artificial snow, in accordance with the invention, is shown.

[0033] This spraying device 1 is particularly suitable for equipping a snowmaking installation which notably includes a pole (not shown).

[0034] In the case of such a snowmaking installation, the pole is fixed at one end in the ground, for example at the level of a technical shelter, and it comprises a free end on which the spraying device 1 is arranged.

[0035] Thus, this spraying device 1 overhangs the ski slope by around ten meters and is generally called a “snow head”.

[0036] This snowmaking installation is supplied with pressurized water and pressurized air by supply lines (not shown) extending in particular along the slope. These supply lines include pipes (not shown) allowing the transport of pressurized air and pressurized water to each snowmaking installation for the supply of pressurized water and pressurized air to the spraying device.

[0037] These supply lines also include general shut-off valves (not shown), located at the foot of each pole (in particular within the associated technical shelter), allowing the pressurized water and air supplies to be closed or opened.

[0038] The spraying device 1 comprises a support body 2, for example made of aluminum, delimited by a front face 21, a rear face 22, a top face 23 and a bottom face 24.

[0039] It also comprises a pressurized water supply means in the form of a pressurized water supply conduit 3 and a pressurized air supply means, in the form of a pressurized air supply conduit 4, which both open into the underside 24 of the support body 2.

[0040] The pressurized water and pressurized air are conveyed in a conventional manner, via the pole, from the general shut-off valves to the pressurized water 3 and pressurized air 4 supply lines of the support body 2 of the spraying device 1.

[0041] The support body 2 of the spraying device 1 comprises: at least one water spray element 5 of the nozzle type with a constant opening section, supplied by the pressurized water supply conduit 3, at least one water spray element 6 of the nozzle type with a variable opening section, supplied by the pressurized water supply conduit 3, at least one element 7 for spraying a mixture of air and water, in the form of a nucleating element, supplied by said pressurized water supply means 3 and by said pressurized air supply means 4, different control valves (in this case two in number: a first control valve 8 and a second control valve 9) controllable in opening and closing, for adjusting the pressurized water supply of said at least one water spray element of the nozzle type with a constant opening section 5, and of said at least one water spray element of the nozzle type with a variable opening section 6, control means 10,11 capable of controlling the opening and closing of said first and second control valves 8 and 9 differently, so as to authorize / prohibit the supply of pressurized water and pressurized air to the different spray nozzles 5, 6.,

[0042] For the sake of simplicity, in the remainder of the description, the water spraying elements 5 and 6 are called "nozzles" and the water and air spraying elements 7 are called "nucleating elements".

[0043] Several nozzles with constant opening section 5, and / or several nozzles with variable opening section 6, can be arranged on the support body 2. And this support body 2 also comprises at least one nucleation element 7.

[0044] In the illustrated embodiment, as can be seen in particular on the Figure 1, the support body 2 of the spraying device 1 comprises: a nozzle 6 with a variable opening section arranged centrally, a plurality of nozzles 5 with a constant opening section (in this case eight in number), arranged around said nozzle with a variable opening section 6 (distributed on a circle centered on the latter), a plurality of nucleation elements 7 (in this case four in number), arranged between the nozzle 6 with a variable opening section and the nozzles 5 with a constant opening section (distributed on a circle centered on the nozzle 6 with a variable opening section).

[0045] Here, four nozzles 5 with constant opening section are arranged above the horizontal plane passing through the nozzle 6 with variable opening section; and four nozzles 5 with constant opening section are arranged below this horizontal plane.

[0046] These different nozzles 5, 6 and nucleation elements 7 are here arranged in the upper part of the front face 21 of the support body 2.

[0047] The first control valve 8 ensures the adjustment of the pressurized water supply to the nozzles 5 with constant opening section.

[0048] The second control valve 9 ensures the adjustment of the pressurized water supply to the nozzle 6 with variable opening section.

[0049] And for their part, the nucleation elements 7 are directly supplied by the pressurized water supply conduit 3 and by the pressurized air supply conduit 4, without intervention of said first and second control valves 8, 9. This supply of the nucleation elements 7 is therefore managed directly by the upstream general valves (not shown) located in the technical shelter at the foot of the equipped pole.

[0050] The two control valves 8 and 9 are arranged in parallel, each on the pressurized water supply pipe 3; they manage the water supply to the nozzles 5 and 6 via suitable supply pipes arranged in the support body 2.

[0051] The control valves 8 and 9 here each have a generally cylindrical shape and they each pass through the support body 2, from its front face 21 to a technical chamber 25 arranged at its rear face 22; these two control valves 8 and 9 can be of the type as described in document FR-2 995 391.

[0052] Each control valve 8, 9 more particularly comprises a fixed body 81, 91, in the general shape of a tube fixed to the support body 2 by suitable fixing means, delimiting an internal housing in which a mobile body 82, 92 is housed, with the interposition of suitable sealing joints.

[0053] The movable body 82, 92 can be moved in translation relative to the fixed body 81, 91 to manage the passage of pressurized water towards the nozzles 5, 6. This movable body 82, 92 opens, via its rear end, into the technical chamber 25 of the support body 2, to allow it to be maneuvered by the aforementioned control means 10, 11.

[0054] These control means 10, 11 consist, for each valve 8, 9, of an axial endless screw 83, 93, controlled in rotation by an actuator 84, 94.

[0055] The two actuators 84 and 94 are independent of each other and can be brushless motor type actuators controlled by an electronic card.

[0056] The management of the various actuators is ensured by a suitable electronic card, for example housed in the technical chamber 25 of the support body 2. This electronic card preferably has means of communication allowing remote software (provided in the shelter valve or in the engine room for example) to take control of it.

[0057] The sequencing of the position of each moving body 82, 92 is carried out by intervening electrically, electronically or in software on the actuators 84, 94 of the worm screws 83, 93.

[0058] In particular, in the present case, each mobile body 82, 92 can be in 3 possible states: closed, open or emptying. a / When closed, the chamber downstream of the valve 8, 9 is sealed from the upstream water circuit. b / When open, the downstream chamber is supplied by the upstream circuit; if necessary, this position can be adjusted, by fine positioning of the movable body 82, 92, in order to achieve a gradual increase or decrease in flow rate. c / When draining, the downstream chamber is put into communication with the upstream air circuit.

[0059] This allows the water remaining in the circuits, when the valve is closed, to be expelled by the nozzles and correctly sprayed despite the low water pressure, by creating an air and water mixture similar to what is done in an internally mixed snow gun (see for example the devices described in documents FR-2 743 872 or FR-2 995 391); under these conditions the quantity of residual water will be transformed into snow and the quality of snow at the end of production will not be altered by the drain water.

[0060] As on water, the profile of the moving body 82, 92 can be designed to be progressive so that the downstream air pressure is controlled. Reducing the air pressure makes it possible, for example, to limit the risks of freezing at very low temperatures.

[0061] The use of precise positioning, such as that permitted by brushless motors or stepper motors, makes it possible to regulate the water or air pressure in the downstream circuit without using a downstream pressure sensor or flow meter.

[0062] This type of actuator also makes it possible to optimize the transition times from one state to another by controlling the rotation speed and therefore allowing rapid approaches without overshooting positions.

[0063] This means that the operation of the spraying device can be adapted in real time to the overall context of the snowmaking installation.

[0064] The spray nozzles 5 consist of nozzles with a constant opening section of the full and flat jet type. For example, nozzles known under the name "fanjet" are used, such as those described in document FR 2 995 391, or in document WO 97 / 18421, or marketed under the name Veejet (registered trademark), by the company Spraying Systems (USA).

[0065] Each of these spray nozzles 5 comprises a tubular body 51 which terminates at its front end 52 in a water outlet orifice 53. These nozzles 5 are arranged in cavities provided for this purpose in the support body 2; and each of them is supplied with pressurized water by the pressurized water supply conduit 3 and by the control valve 8, by means of an appropriate internal pipe. Each of these nozzles 5 is adapted to propel pressurized water through the orifice 53 of its front end 52 which opens into the front face 21 of the support body 2.

[0066] The flow rate of the nozzles 5 is constant and is a function, on the one hand, of the dimensions of the water outlet orifice 53 and on the other hand of the water pressure in the pressurized water supply conduit 3.

[0067] If necessary, at least two constant opening section nozzles of the spray head 1 have different opening sections to adjust the flow rate to the desired operating temperature.

[0068] Typically, a flow rate of 1.2 to 3 m3 / h at 20 bars should be ensured.

[0069] For example, eight identical nozzles 5 can be used, each with a flow rate of 3 L / min (making it possible to obtain a total flow rate of 1.44 m 3 < / h).

[0070] Depending on the case, it is also possible to combine nozzles of different sections: for example, four nozzles 5 in the upper position, each having a flow rate of 4 L / min (making it possible to obtain a flow rate of 0.96 m 3 / h), and four nozzles 5 in the lower position, each having a flow rate of 2 L / min (making it possible to obtain a flow rate of 0.48 m 3 / h)

[0071] Furthermore, it can be advantageous to have a different flow rate at the top and bottom of the jet since the exchanges with the ambient air are different in these two areas.

[0072] The spray nozzle 6 consists of a nozzle with variable opening section of the thin-walled hollow jet type, for example as described in document EP-1 386 668.

[0073] This nozzle 6 comprises a fixed tubular body 61 which contains an axial throttle member in the form of a valve 62 which can move in translation, ensuring the formation of an annular opening of variable section at their front end 63.

[0074] The nozzle 6 is arranged in a cavity provided for this purpose in the support body 2; and it is supplied with pressurized water by the pressurized water supply conduit 3 and by the control valve 9, by means of a suitable internal pipe. The nozzle 6 is adapted to propel pressurized water through the annular opening of its front end 63 which opens into the front face 21 of the support body 2.

[0075] The throttling member 62 is associated with control means 64 which ensure its translational movement to adjust the section of its front annular opening 63 for water propulsion, consisting of an axial endless screw 641 controlled in rotation by an actuator 642.

[0076] The actuator 642 is housed in a technical chamber 26 arranged in the rear face 22 of the support body 2 and into which the rear end 621 of the axial throttle member 62 opens.

[0077] The actuator 642 may be a brushless motor type actuator controlled by the aforementioned electronic card.

[0078] For information purposes only, the flow rate of such a spray nozzle 6 can range from 1.2 m 3 < / h to 2.4 m 3 < / h under 20 bars.

[0079] Where appropriate, the same spraying device 1 may comprise several nozzles with variable opening section 6, identical or having different structures, for example in terms of optimum flow rate ranges.

[0080] The nucleation elements 7 consist of pressurized air / water spray nozzles, well known to those skilled in the art, for the formation of ice microbeads intended to promote the production of ice crystals by the associated water spray nozzles 5, 6. Such nucleation elements 7 are for example described in document EP 1 053 440.

[0081] Each of these nucleation elements 7 comprises a tubular body 71 which ends at its front end 72 with an outlet orifice 73 for a mixture of water and air.

[0082] These nucleating elements 7 are arranged in cavities provided for this purpose in the support body 2; and each of them is supplied with pressurized water by the pressurized water supply conduit 3, and with pressurized air by the pressurized air supply conduit 4, by means of appropriate internal pipes, here without the intervention of the control valves 8 and 9. Method of implementing the spraying device

[0083] This control of the control valves 8, 9 can be managed to operate one type of nozzle 5, 6 rather than another, or both simultaneously, depending on the weather conditions present, in particular depending on the ambient temperature on the site, with a view to producing the best possible quality of snow.

[0084] To do this, it is taken into account that nozzles with a constant opening section generally allow the production of good quality snow at higher temperatures than nozzles with a variable opening section, with the disadvantage that the flow rate is low and constant.

[0085] On the other hand, nozzles with variable opening section have the advantage of a progressive and therefore maximum flow rate over a wide temperature range, but with the disadvantage of a lower starting temperature of 1 to 2°C.

[0086] In the context of such management, preferably a first temperature threshold S1 (for example of the order of - 4°C) and a second temperature threshold S2 higher than S1 (for example of the order of - 2°C) are taken into account, and: the control valve 8 for supplying water to the nozzles with a constant opening section 5 is closed, as well as the control valve 9 for supplying water to the nozzles with a variable opening section 6, above the threshold S2, so as not to attempt to produce snow when the ambient temperature is considered too high; the first control valve 8 is opened and the second control valve 9 is closed, between the aforementioned thresholds S1 and S2, to produce snow using only the nozzles with a constant opening section 5, when the ambient temperature is considered average; and the second control valve 9 is opened and the first control valve 8 is closed below said threshold S1, to produce snow using only the nozzle(s) with a variable opening section 6, when the ambient temperature is considered low.

[0087] In addition to the management method described above, taking into account a third temperature threshold S3 lower than S1: below said threshold S3, the second valve 9 for controlling the water supply to the variable section nozzle or nozzles is actuated in the open position, as is the first valve 8 for controlling the water supply to the constant section nozzle or nozzles.

[0088] Preferably, the open positions of the two control valves 8 and 9 are overlapped on said threshold S1 or close to this threshold S1, to ensure a flow rate during the transition.

[0089] In an alternative embodiment, the two control valves 8 and 9 are actuated in the open position below the threshold S1.

[0090] The flow rate of the variable opening section nozzles 6 is advantageously increased with the decrease in temperature, until a maximum flow rate is reached.

[0091] Preferably, a minimum opening position of the throttling member of the nozzle(s) with variable opening section is provided, so that the start of production takes place with good spraying (with large drops generated when such nozzles are opened).

[0092] The operation of the spraying device is managed in particular from measurements of weather conditions (temperature, humidity, wind speed and direction), water and compressed air pressures and the measured water flow rate.

[0093] And starting from the same spray head, different types of nozzles can be used independently or in combination to try to produce the best quality and / or quantity of artificial snow.

Claims

1. A spraying device for the production of artificial snow, provided with a support body (2) comprising pressurized water supply means (3), pressurized air supply means (4), and a plurality of water spraying elements of the spraying nozzle type (5, 6), said support body (2) comprises: - at least one water spraying element of the constant opening cross-section nozzle type (5), suitable for spraying only water, in order to produce water droplets capable of producing snow, supplied by said pressurized water supply means (3), and - at least one element for spraying a mixture of air and water, in the form of a nucleation element (7) suitable for the formation of ice microbeads intended to promote the production of ice crystals by the associated water spray nozzles (5, 6) supplied by said pressurized water supply means (3) and by said pressurized air supply means (4), characterized in that said support body (2) still comprises: - a first control valve (8), whose opening and closing can be controlled, for adjusting the pressurized water supply of said water spraying element of the constant opening cross-section nozzle type (5), - at least one water spraying element of the variable opening cross-section nozzle type (6), suitable for spraying only water, in order to produce water droplets capable of producing snow, supplied by said pressurized water supply means (3), and - a second control valve (9), whose opening and closing can be controlled, for adjusting the pressurized water supply of said at least one water spraying element of the variable opening cross-section nozzle type (6), and - control means (10, 11) adapted to control differently the opening and closing of said first and second control valves (8, 9).

2. The device according to claim 1, characterized in that said at least constant opening cross-section nozzle (5) consists of a spraying nozzle of the flat and full jet type, and in that said at least one variable opening cross-section nozzle (6) consists of a spraying nozzle of the thin-wall hollow jet type.

3. The device according to any one of claims 1 or 2, characterized in that each of said control valves (8, 9) has its own associated control means (10, 11).

4. The device according to claim 3, characterized in that said first control valve (8) and said second control valve (9) are each operated in translation by an endless screw (83, 93), controlled in rotation by an actuator (84, 94), the sequencing of the position of said first and second control valves (8, 9) being made by intervening electrically, electronically or through a software on the actuators (84, 94) of said endless screws (83, 93).

5. The device according to any one of claims 1 to 4, characterized in that it comprises at least two constant opening cross-section nozzles (5) whose opening cross-sections are different from each other.

6. The device according to claim 1, characterized in that the water supply (3) and air supply (4) of said nucleation element (7) is made independently of said first and second control valves (8, 9).

7. The device according to claim 1, characterized in that said support body (2) comprises: - a variable opening cross-section nozzle (6), - a plurality of constant opening cross-section nozzles (5), arranged about said variable opening cross-section nozzle (6), and - a plurality of nucleation elements (7), arranged between said variable opening cross-section nozzle (6) and said constant opening cross-section nozzles (5).

8. The device according to claim 1, characterized in that said at least one nozzle with variable opening cross-section nozzle (6) comprises a movable axial throttling member (62) for adjusting its opening section (63), and in that the movement of said axial throttling member (62) is controlled by an actuator (642).

9. A method for implementing a spraying device (1) according to claim 1, for making artificial snow, wherein said method consists, taking into account of a first temperature threshold S1 and a second temperature threshold S2 higher than S1, in: - operating to the closed position said first water supply control valve (8) of said at least one constant cross-section nozzle (5) and said second water supply control valve (9) of said at least one variable cross-section nozzle (6), above said threshold S2, - operating to the open position said first control valve (8) and operating to the closed position said second control valve (9), between said thresholds S1 and S2, and - operating to the open position said second control valve (9) and operating to the closed position said first control valve (8), under said threshold S1.

10. The method according to claim 9, characterized in that it consists in making the open positions of said first and second control valves (8, 9) overlap on said threshold S1, or near said threshold S1.

11. The method according to any one of claims 9 or 10, consisting, taking into account a third temperature threshold S3 lower than S1, in operating to the open position said first water supply control valve (8) of said at least one constant cross-section nozzle (5) and said second water supply control valve (9) of said at least one variable cross-section nozzle (6), under said threshold S3.

12. A method for implementing a spraying device according to claim 1, for making artificial snow, wherein said method consists, taking into account a first temperature threshold S1 and a second temperature threshold S2 higher than S1, in: - operating to the closed position said first water supply control valve (8) of said at least one constant cross-section nozzle (5) and said second water supply control valve (9) of said at least one variable cross-section nozzle (6), above said threshold S2, - operating to the open position said first control valve (8) and operating to the closed position said second control valve (9), between said thresholds S1 and S2, and - operating to the open position said second control valve (9) and said first control valve (8), under said threshold S1.

13. The method according to any one of claims 9 to 12, characterized in that it consists in providing a position of minimum opening of said at least one variable opening cross-section nozzle (6).

14. The method according to any one of claims 9 to 13, characterized in that it consists in increasing the flow rate of said at least one variable cross-section nozzle (6) with the decrease of the temperature, until reaching a maximum flow rate.