FR2908504A1 - DEVICE FOR SPRAYING A VARIABLE FLOW FLUID FOR THE FORMATION OF ARTIFICIAL SNOW - Google Patents

Abstract

The subject of the invention is a snow gun incorporating at least one fluid spraying device comprising on the one hand a fluid supply duct (24) comprising a convergent (26) ending in a reduced section ( 28), and secondly, an element for varying the flow rate arranged at or after the reduced section (28), characterized in that the element for varying the flow rate is under the form of a deflector (36) capable of moving in a direction secant to the axis (30) of the conduit (24).

Description

DEVICE FOR SPRAYING A FLUID WITH VARIABLE FLOW FOR TRAINING

  The present invention relates to a device for spraying a variable flow fluid for the formation of artificial snow. An artificial snow production facility includes snow guns reported at the end of poles. These guns comprise at least one nozzle via which is sprayed a fluid including water. Nucleation means are also provided to promote the formation of crystals. For the production of artificial snow, it is known that it is important to adjust the flow rate of the sprayed fluid as a function of the atmospheric temperature to produce an optimal amount of snow.

  In variable-rate snow cannons, there are mainly two families. The snow guns of the first family include a plurality of fixed rate nozzles, wherein the rate of the gun is adjusted according to the number of nozzles in the on state. This type of snow gun does not give full satisfaction because to obtain a substantially continuous flow rate variation, it is necessary to provide a large number of nozzles which tends to complicate the gun in that for each nozzle it is necessary to provide means for managing the passage or not of the fluid. The snowmakers of the second family comprise at least one variable flow nozzle. Thus, it is possible to theoretically adjust the flow rate of the fluid as a function of the meteorological conditions.

An example of a variable-rate snow gun is described in WO94 / 10516. According to this document, the nozzle is in the form of a nozzle duct with, depending on the direction of flow of the fluid, a convergent followed by a divergent 5 having a longitudinal axis corresponding to the direction of the fluid. To control the passage of the fluid, the nozzle comprises a valve capable of cooperating with a seat formed by the divergent. In a simplified form, the valve has a full frustoconical shape which cooperates with the hollow frustoconical shape of the divergent. According to a more elaborate variant described in EP-1.386.668, the valve and the diverging can have elliptical shaped sections. According to these embodiments, a hollow jet is obtained because of the shadow zone resulting from the valve disposed substantially centrally with respect to the fluidic vein. Insofar as the jet is hollow, it is necessary to provide a relatively large passage diameter to obtain a significant flow, suitable for snow production, of the order of 3 to 20 cm. According to the embodiments described in these two documents, the flow variation is obtained by translating the valve along the longitudinal axis of the nozzle to move it more or less from its seat. For this purpose, the valve is attached to the end of a shaft disposed along the longitudinal axis, substantially centered with respect to the fluidic vein, said shaft being translated by an actuator. Insofar as the annular passage zone has a relatively large diameter, to obtain a gradual variation without step, it is necessary that the pitch between two stable positions of the valve is relatively small to obtain a variation of the low flow rate between two stable positions and to obtain a substantially continuous progression.

According to another constraint, the valve being disposed in the vein of the fluid and its surface opposing the advancement of the fluid being relatively large, the force exerted by the fluid on the valve is relatively important. The kinematic chain between the actuator and the valve does not make it possible to obtain precise control of the flow rate by means of the actuator alone because of the large stresses to which the valve is subjected and the inherent play of the kinematic chain which induce a difference between the theoretical flow rate that can be determined by the actuator and the actual flow rate. Therefore, it is necessary to provide means for controlling the actual flow that can inform the actuator to enable it to correct the positioning of the valve as a function of the difference between the theoretical flow and the actual flow measured. Due to all these constraints, this type of snow cannon is relatively complex in controlling the movement of the valve and the kinematic chain inducing said displacement which affects its reliability and results in manufacturing and maintenance costs. high. Also, the present invention aims at overcoming the drawbacks of the prior art by proposing a snow gun incorporating at least one device for spraying a variable flow fluid for the formation of artificial snow of simple design, making it possible to reduce the manufacturing and maintenance costs. For this purpose, the subject of the invention is a snow gun incorporating at least one fluid spraying device comprising on the one hand a fluid supply duct comprising a convergent ending in a reduced fluid passage section, and on the other hand, an element for varying the flow rate disposed at or after the reduced section, characterized in that the element for varying the flow rate is in the form of a deflector capable of moving in a secant direction to the axis of the conduit.

Further features and advantages will become apparent from the following description of the invention, a description given by way of example only, with reference to the accompanying drawings in which: - Figure 1 is a perspective view of the upper part; FIG. 2 is a front view of a spraying device according to the invention that can be incorporated into a snow cannon-head; FIG. 3 is a section along the line; III-III of Figure 2 of a spraying device according to the invention, - Figure 4 is a section illustrating in detail the elements placed in the circle IV of Figure 3, - Figure 5 is a perspective with a section III-III of Figure 2 illustrating a spraying device according to the invention, - Figure 6 is a perspective with a section along the plane VI-VI of Figure 3 illustrating a spraying device according to the invention, and FIG. erspective with a section along the plane VII-VII of Figure 3 illustrating a spraying device according to the invention. In FIG. 1, there is shown at 10 a snow gun comprising a head 12 attached to the end of a pole 14.

The pole makes it possible to maintain the height of the head in order to improve the spread of the snow created and comprises inside at least one duct, and generally several, making it possible to supply fluid to the head. This boom is not more detailed because it is known to those skilled in the art and does not constitute an essential element of the invention.

The head 12 comprises at least one device 16 for spraying a fluid, in particular water for the manufacture of snow, capable of generating a jet 18.

To initiate crystal formation, the head 12 may include at least one nucleating device 20 capable of ejecting germs into the environment of the jet (s) from the at least one spraying device. According to an exemplary embodiment, the nucleation can be obtained by the expansion of a gas under pressure such as compressed air. The nucleation device 20 is not more detailed because it is known to those skilled in the art. The head comprises different ducts or ducts ensuring the fluidic continuity between the ducts opening at the end of the pole and the one or more spray devices 16, and possibly the nucleating device or devices. According to the invention, the spraying device 16 is at a variable rate. It is illustrated alone in Figures 2 to 7. It comprises a body 22 having a conduit 24, one end opens out of the body 22 so as to form a jet 18. This conduit 24 comprises at its open end Thus, the area of the duct sections decreases to a section 28 corresponding to the open end of the duct 24. The convergent 26 may be followed by a divergent according to the variants.

The reduced section 28 of the duct after the convergent makes it possible to obtain the formation of droplets which are projected outside the spraying device 16. The shape of the reduced section 28, which may not be circular, makes it possible to define the shape of the jet 18.

In order to promote the formation of droplets and in particular to reduce their dimensions, it is possible to dispose an obstacle forming a jet breeze at or after the reduced section 28.

According to a preferred embodiment and illustrated in detail in FIG. 4, the duct 24 has an oblong section and comprises a convergent 26 whose section decreases to a reduced section 28. This duct 24 has a longitudinal axis 30 and each section comprises a first semi-circular portion at the top, a second semi-circular portion at the bottom, said portions being connected by straight portions substantially vertical. Thus, the oblong shape has a major axis in a vertical plane. To form the convergent 26, the rectilinear portions tend to be progressively reduced until the semicircular portions meet to obtain a substantially circular shape at the reduced section. the level of which opens the conduit comprises a first flat surface 32 substantially perpendicular to the longitudinal axis 30 and a second flat surface 34 disposed in the extension of the axis 30 and substantially perpendicular to the first surface 32.

As illustrated in FIG. 3, the first surface 32 and the second surface 34 form a Ve disposed in planes at approximately 45 to the horizontal. Thus, as illustrated in FIG. 2, an elliptical shaped jet with a substantially horizontal major axis is obtained. This configuration makes it possible to obtain a better distribution of the snow.

According to the invention, the spraying device 16 comprises means for adjusting the flow rate. These means comprise at least one deflector 36 capable of interfering more or less significantly with the fluidic vein or the jet by translating in a secant direction to the conduit 24 and thus to the fluidic vein. This deflector 36 is provided at or after the reduced section 28.

According to one embodiment, the deflector 36 is in the form of a cylindrical slider of axis 38 slidable in a bore 40 opening at the reduced section 28, the cylindrical slider 36 having a free end 298 42, capable of interfering with the fluidic vein, substantially flat perpendicular to the axis 38. Advantageously, the deflector 36 can translate in a direction perpendicular to the major axis of the ellipse formed by the jet, forming an angle of 5 l 135 order with the axis 30 of the duct 24, between a high position in which it completely disengages the reduced section 28 and a low position in which it closes the reduced section 28. An actuator is provided to generate the translation movement of the deflector 36. According to the simplified example and illustrated in the various figures, the actuator 10 is in the form of a wheel provided at the upper end of the slide. u, said slide having a threaded portion capable of cooperating with a threaded portion formed at the bore receiving the slider to convert a rotational movement into translational motion. Of course, other kinematics can be envisaged to generate the translational motion. In the same way, this movement can be obtained thanks to a controlled motorization to automate the regulation of the flow. Finally, an actuator can be provided for each spraying device or an actuator can control several baffles of different spraying devices.

According to one characteristic of the invention, the diameter of the slide must correspond substantially to the diameter of the half circles of the sections of the duct 24 which form a circle at the reduced section 28. In addition, the intersection of the flat surfaces 32 and 34 must be arranged at the axis of the slide.

By way of example, the slider has a diameter of the order of 3 mm. According to one embodiment, the spraying device comprises a sleeve 44 of cylindrical section with axis 38, with a V-shaped cut with an edge 46 substantially perpendicular to the axis 38 and passing through said axis 38.

The V-shape defines the first surface 32 and the second surface 34. These surfaces make an angle of the order of 90 substantially centered with respect to a plane substantially perpendicular to the axis 38. The body of the spray device comprises a bore 48 having an axis 30 disposed in the plane of the second surface 34 and in a plane perpendicular to the edge 46. This bore 48 coincides with the conduit 24 formed in part in the body and the sleeve 44. In addition, the sleeve 44 comprises a bore 40 of axis 38, in which the deflector 36 can move, and opening into the conduit 24.

The dimensions of the jet can be adjusted by modifying the Vee cut, in particular by changing the angle between the first surface 32 and the second surface 34, and / or the shape and dimensions of the reduced section 28 and / or the shape. and the dimensions of the deflector 36. The advantages of such a spraying device are as follows: The fact that the deflector moves in a direction perpendicular to the major axis of the elliptical shape of the solid jet makes it possible to obtain better resistance to gel because this arrangement makes it possible to obtain a more compact head. The displacement direction of the deflector being offset, and making an angle of about 45 with the fluidic vein simplifies the design of the mechanism for moving the deflector. Moreover, according to this configuration, the deflector makes it possible to vary the flow and the exit angle of the jet. Thus, the higher the flow, the greater the axis of the ellipse formed by the jet. This contributes to a better distribution of the snow.

Since the deflector is disposed outside the fluidic vein, it is not subjected to the static pressure of the fluid and the resulting forces.

Since the surface of the deflector capable of receiving the fluid is oriented at 45 relative to the direction of the fluid, the deflector is only subjected to a portion of the dynamic pressure. Using a deflector with a small diameter at the reduced section 5 to adjust the passage section limits the forces on said deflector. This makes it possible to use less expensive actuators and offers the possibility of implanting an actuator for each spraying device. The fact of choosing a cylindrical deflector offers a great latitude of choice concerning the actuator.

Finally, this solution makes it possible to completely clear the reduced section 28 to allow the evacuation of any impurities contained in the water.

Claims (10)

  A snow barrel incorporating at least one fluid spraying device comprising on the one hand a fluid supply duct (24) comprising a convergent (26) ending in a reduced fluid passage section (28), and on the other hand, an element for varying the flow rate disposed at or after the reduced section (28), characterized in that the element for varying the flow rate is in the form of a deflector (36). ) capable of moving in a secant direction to the axis (30) of the conduit (24).   2. Snow cannon according to claim 1, characterized in that the outer surface of the spray device at which the conduit (24) opens out comprises a first flat surface (32) and a second flat surface (34) substantially perpendicular to the first surface (32), said two surfaces joining at a substantially horizontal edge (46) intersecting with the conduit (24).   3. Snow gun according to claim 2, characterized in that the first surface (32) and the second surface (34) are at an angle of approximately 90.   4. Snow gun according to claim 2 or 3, characterized in that the second surface (34) is disposed in the extension of the axis (30) of the conduit (24) for supplying fluid.   A snow cannon according to any one of claims 2 to 4, characterized in that the first surface (32) is disposed in the plane of the reduced section (28).   6. Snow gun according to any one of claims 2 to 5, characterized in that the deflector (36) is in the form of a slider capable of sliding in a direction perpendicular to the edge (46) in a Bore (40) opening at the reduced section (28), the slider having a free end (42) capable of more or less interfering with the fluid stream flowing in the conduit (24).   7. Snow gun according to claim 6, characterized in that the free end (42) is substantially flat and perpendicular to the axis (38) of the slide. 5   8. Snow cannon according to any one of the preceding claims, characterized in that the translational direction of the deflector (36) is an angle of approximately the order of 135 with the axis (30) of the duct (24).   9. Snow gun according to any one of the preceding claims, characterized in that the duct (24) has an oblong section with a major axis 10 in a substantially vertical plane, the rectilinear portions of said oblong shape tending to gradually reduce. to form the convergent (26).   10. A snow cannon according to claim 9, characterized in that the deflector (36) has a circular section of diameter substantially identical to the diameter of the reduced section (28).