EP0242279A1 - Process and apparatus for the pneumatic transport of snow - Google Patents

Abstract

The invention relates to a method and device for conveying in translation a heap of snow with a view to delivering it by a sampling member in a fixed position (1) with which the other members of the pneumatic transport equipment are associated.

The conveying speed is controlled by a servo device and the height of the snow pile is controlled by a clipping device (9).

Description

The present invention relates to a pneumatic method and device for transporting natural or artificial snow intended for snowmaking or snow removal or fire protection, and more particularly the conditions for removing snow.

It is known from French patents 2,289,414 and 2,327,172 to snow the ski slopes by removing snow from a pile and transporting it pneumatically to the place of use by means of a pipe. The apparatus described in these patents comprises a fan delivering air into a transport pipe on which a snow injector is provided. The installation associated with the transport pipe can be fixed, the snow removal member, the injector and the air generator then being permanently placed at their place of use. The installation can also be mobile and includes the same members mounted on a vehicle. The snow removal device described always moves in a heap of snow or a layer of stationary snow. It is either a screw delivering a pile of snow into conical slices of various angles at the top, one end being secured to an articulated fixing point, the other end describing circles whose radius is increasing, or a screw mounted on a mobile carriage delivering a pile of snow in transverse sections successively, that is to say a removal member movable on the snow while being mounted on a vehicle.

In document FR-A-2,327,172 the sampling device placed at the head of the pipe of the fixed installation refers to that described in the claims of patent FR-A-2,289,414, that is to say as described above. Thus, these patents describe an organization of the snow removal in which the heap of snow or the layer of snow are stationary, the removal member having to move, including in the so-called fixed installation.

It is the same in French patent 2,422,771 where the sampling member consisting of a cutter or turbo-cutter moves on an adjustable arm.

It is also the same in the European Patent Application ^No. 106,731 where only the air generator can be a fixed station, the sampling device is always associated with the vehicle for delivering the heap or the snow that remains motionless.

The sampling member consisting of screws as described in patent FR-A-2,289,414 does not ensure a seal between the internal space of the pipe and the atmosphere where the air pressures are different ; this results in poor pneumatic efficiency due to leaks air from inside the pipe to the outside. The realization implements quite complex mechanisms. It is also known that snow is a material which quickly causes stuffing phenomena and therefore blocking on the conveyor screws.

The sampling device consisting of a snow blower or a single or double drum turbo cutter is effective, but its use has always been envisaged by being moved over the pile or layer of snow by means of a vehicle. This arrangement requires a tracked vehicle capable of moving over snow, the cost of which is high and the driving of which is made very difficult by the need to cut the snow regularly.

This result being very difficult to achieve, this results in a very irregular snow flow in the pipe which results in a risk of blockage and an actual average transport flow rate much lower than the theoretical maximum flow rate of the installation, also due to loss of time generated by vehicle maneuvers.

The use of a wheeled vehicle to move the removal member in snow removal operations in pneumatic transport has the same drawbacks as those described above.

The present invention aims to remedy these drawbacks. To this end, it relates to a process and a device for pneumatically transporting snow, particularly comprising a conveying apparatus making it possible to move a pile of snow towards a sampling and lump removal member in a fixed position, a sampling member associated with an injector also fixed. This method and this implementation device thus make it possible to control the thickness of the snow absorbed by the removal member as well as the conveying speed and consequently the snow flow to be introduced into the transport pipe.

An object of the present invention consists of a pneumatic snow transport method comprising at least one drive source driving an air generator, a snow injection member in the transport pipe producing a mixture of air and snow, the latter coming from a pick-up member, drive means for driving said injection and pick-up members linked to or independent of said drive source, characterized in that said injection and snow-picking members are in a fixed position, and in that a heap of snow is moved towards the sampling member by a conveying means according to a controlled translation speed and thickness.

The injection and withdrawal organs are for example respectively a rotary valve and a cutter as described in the patents cited above. The snow is brought to the conveying device either by being pushed by the blade of a tamping machine, for example, or transported by a "loader" type public works machine.

Another object of the invention consists of a device for implementing the method comprising at least one motor source driving an air generator, at least one snow injection member associated with a transport pipe producing a mixture of air and snow, at least one removal member, drive means for driving said members linked to or independent of said drive source, characterized in that said injection and removal members are in a fixed position and in that it further comprises a conveying means displacing in translation the snow heap towards the removal member and a clipping device having the function of controlling the thickness of the snow heap reaching the removal member.

The means of conveying the snow mass may consist of a conveyor belt equipped with transverse spikes in order to drive the snow mass and of means for driving said conveyor belt.

The conveying means can also consist of transverse crampons with a view to driving the snow, sliding on a fixed floor, driven by two side chains actuated by motor means.

The conveying means are driven by drive means belonging to a group which includes mechanical transmissions, hydraulic transmissions, electrical transmissions and mixed transmissions.

When the sampling member is of the snow cutter or turbo-cutter type, the sampling drum is preferably placed tangentially to the plane of conveyance of the snow mass.

Said drive means provide said conveying means with a translational movement at discontinuous speed called step by step or at constant continuous speed. In both cases, the value of said speed is adjusted and controlled as a function of the power consumed by the sampling device, this depending on the consistency of the snow and constituting one or more setpoint values for regulation by continuous action or discontinuous.

For example, in the case of a hydraulic transmission ensuring the driving of the snow cutter type sampling device, the value of the maximum power not to be exceeded is measured indirectly by measuring the supply oil pressure. of the engine, the oil flow must be constant to ensure a constant speed of rotation. In case if this setpoint is exceeded, a pressure switch activates a hydraulic solenoid valve in order, for example, to interrupt the supply to the hydraulic drive motor of the snow conveying device. When the pick-up device regains a normal resistive power below the set value, measured indirectly, the drive motor of the conveyor device is again supplied, putting the snow back in motion at a predetermined constant speed. In this example, the speed is controlled by servo means acting "all or nothing".

An improvement consists in adjusting said speed of the conveying device by means of permanent regulation according to progressive and continuous values or according to discontinuous values in stages in order to maintain a constant resistance power of the picking member, by measuring for example oil pressure as described above.

The snow flow to be introduced into the pipe depends firstly on the width of the snow mass equal to that of the conveying device which is equal to that of the picking device, secondly on the speed of conveying the snow and thirdly the average height of the snowfall. This average height is determined by a clipping device consisting of scrapers or a conveyor belt as described for the conveying device rotating in the opposite direction to that of the conveying device, placed obliquely, its base being situated at an equal height. to that determined for the pile of snow, and situated a little before the removal member while being fixed to the common frame supporting the injection, removal and conveying members, by suitable means. Said height can be fixed or adjustable. The speed of rotation is determined in such a way that the excess snow is discharged without creating an excessive resistance force against the advancement of the pile of snow when its conveying speed is maximum.

The conveying device and its drive means are fixed to a frame provided with pad (s) when it has to move on snow or on wheels, for the case in particular where it is used for snow removal from traffic lanes or places, although in this case, the use of skates is possible.

On said frame are fixed permanently or removably the injection and withdrawal organs. In the second case, the injection and withdrawal organs can constitute a unit that can be used either on said frame, associated with the conveying device, or on a vehicle as described in the patents cited above.

Likewise, the air generator is placed in a fixed or removable manner on a frame equipped with a thermal or electric motor and connected to the injection member by a flexible air duct. This frame can be secured to a sledge that can either be towed on the snow, or placed on a vehicle. If the attachment is removable, the air generator can be used on this sled frame driven by said engine either in association with the assembly of injection, withdrawal and conveying members, or in association with the injection members and sampling mounted on a vehicle as described in the European patent application ^No. 106,731; the air generator can also be carried by the vehicle carrying the injection and sampling organs as described in the cited patents.

Another variant of the invention provides for a snow cutter or turbo-cutter type withdrawal member having several snow supply outlets each connected to an injection member, each connected to a pneumatic transport pipe. The width of the conveying device is equal to that of the removal member. Thus, with a common sampling device and a common conveying device, it is possible to supply one or more transport pipes making it possible to snow a runway with a much higher flow rate or also, to snowfall several tracks simultaneously.

Another variant provides for the possibility of associating several unitary devices one beside the other. Thus, several devices associated transversely increase the conveying width as described in the previous variant while also making it possible to simultaneously supply several pipes.

Another variant provides for associating with the conveyor device connected to its withdrawal and injection member, one or more other conveyor devices in the longitudinal direction in order to linearly increase the stock of snow that can be conveyed according to a straight line or according to a curve segmented by each of the conveying devices.

A method and an apparatus are thus available which considerably improve the conditions of use for the pneumatic transport of snow by the appreciable increase in the average flow rate of snow removed, by the reduction in operating costs resulting from not immobilization of a high-power carrier vehicle, by improving the pneumatic efficiency through the use of sufficiently leaktight injectors unlike the conveying and introduction screws described in patent FR-A-2,289,414, and by simplification of use since the operator's task is simply to push or load the snow onto the conveyor device.

• La figure 1 montre schématiquement en perspective un tel disposi­tif de convoyage associé aux autres dispositifs sur un site de travail. La ridelle est en vue fragmentée.
• La figure 2 montre schématiquement de profil l'ensemble des orga­nes de convoyage, de prélèvement et d'injection.
• La figure 3 montre le schéma du système d'asservissement de la vi­tesse du dispositif de convoyage à la pression d'huile d'alimentation du moteur de l'organe de prélèvement de type fraise à neige dans cet exemple.
• La figure 4 montre schématiquement une variante de dispositif de convoyage commun à un organe de prélèvement à deux orifices d'alimentation et commun à deux organes d'injection et à deux canalisations.
• La figure 5 montre schématiquement une variante d'assemblage de trois dispositifs unitaires permettant d'alimenter simultanément trois cana­lisations.
• La figure 6 montre schématiquement une variante d'assemblage d'un dispositif de convoyage complémentaire placé en prolongement linéaire à un dispositif unitaire.

The description which follows, with reference to the accompanying drawings by way of nonlimiting example, will make it possible to understand clearly how the invention is put into practice.

• Figure 1 shows schematically in perspective such a conveying device associated with other devices on a work site. The side wall is in fragmented view.
• FIG. 2 schematically shows in profile all of the conveying, withdrawing and injecting members.
• FIG. 3 shows the diagram of the system for controlling the speed of the conveyor device at the supply oil pressure of the engine of the snow cutter type sampling member in this example.
• FIG. 4 schematically shows a variant of the conveying device common to a withdrawal member with two supply orifices and common to two injection members and to two pipes.
• FIG. 5 schematically shows a variant of assembly of three unitary devices making it possible to supply three pipes simultaneously.
• FIG. 6 schematically shows a variant of assembly of a complementary conveying device placed in linear extension to a unitary device.

For snow removal, as can be seen in FIGS. 1 and 2, the withdrawal member 1 is in a fixed position as well as the injection member 2 of the rotary lock type and are fixed to the sledge 3.

On this same sledge 3 is fixed the conveyor device 4 which includes the snow drive scrapers 5, fixed at their end to the two side chains 6. The latter rotate around the rollers 7 at least two of which are driven by a transmission mechanical or motor 8, hydraulic in the present example. The movement of the scrapers 5 which slide on the floor 14, causes the snow against the picking member 1 which delivers it and sends it to the injector 2. As can be seen in FIG. 2, the picking member 1 is preferably placed tangentially to the conveying floor 14.

To ensure a constant thickness of snow in front of the picking member 1, the conveyor device comprises a clipping member 9 which rotates in the opposite direction to that of the scrapers 5. Thus the excess snow is discharged back onto the device drive in translating snow.

The clipping member 9 is made up of scrapers 10 fixed on two chains 11 driven by a mechanical transmission or by a motor 12, hydraulic in this example. It is fixed to a frame 13 secured to the sledge 3.

In the case where the snow is pushed onto the conveying device 14-4 by a pusher machine 15, only a side drop 16 is maintained in the vertical position to keep the snow. The other two sides, side and rear can either be folded down (17) or removed (rear).

In the case of loading by a loader-loader, it is advantageous to leave the three drop sides in the vertical position.

The air generator 18 is connected to the injector 2 by a flexible conduit 19. The motors, hydraulic in the present example, for driving the various members are supplied by pumps driven in coupling or independently by a either thermal 20, electric or hydraulic motor. In the example considered the heat engine 20, the air generator 18 and their associated equipment are fixed on a sledge 21.

The drive speed of the scrapers 5, therefore the speed of conveying the snow, is controlled by a servo device 22 as seen in FIGS. 1 and 3. This servo device receives as information the pressure of oil from the hydraulic motor 23 of the sampling member 1 through a small conduit 24.

The control device 22 acts on the supply to the hydraulic motor 8 of the conveyor device 4 either by stopping this supply by means of a solenoid valve for example, when said oil pressure exceeds a predetermined value, or by varying the engine power flow 8, therefore the snow driving speed, in order to maintain a constant oil pressure on the engine power 23. This speed variation is a function of the consistency of the snow on which the power consumed by the motor of the sampling device 1 depends. In this case, the servo-control device acts for example on the adjustment of the variable displacement of the pump d motor supply 8.

This control device can take into account in a complementary or independent way the pneumatic power measured, for example, by the air pressure inside the pipe. To achieve this control, as shown in Figure 3, a pneumatic pressure switch receives the air pressure through a small duct 25 connected to the air duct 19. This pressure switch acts by sending a control signal to the hydraulic supply of the motor 8 by all or nothing action or by discontinuous or continuous action according to known regulation techniques.

An alternative implementation of the method provides for the use of a withdrawal member with two or more feed outlets served by a single conveying device as seen in FIG. 4.

A single cutter 26 with two outlets supplies two injection members 27a and 27b connected respectively to the snow transport pipes 28a and 28b. The clipping device 29 is also common.

As shown in FIG. 5, another variant implementation of the method consists in associating several independent devices. This arrangement allows very flexible use of the method, in particular for distributing the sampling devices over several snow accumulation sites or on the contrary to maximize the sampling rate on a single site.

As seen in Figure 6, a complementary conveying device 30 is linearly associated with the main device.

This additional device 30 makes it possible to increase, as in the previous variants, the quantity of snow stored on the conveying device but without thereby increasing the rate of removal and transport. It is advantageous when the pusher machine or the loader machine has to collect snow over a large area requiring a transport time greater than the time of absorption of snow on a single conveying device. This additional device 30 does not include a clipping device. Its drive is provided by a mechanical transmission or by a hydraulic motor 31 for example which is connected to a hydraulic supply circuit by hoses 32 and quick couplers 33.

It goes without saying that for reasons of convenience of operation or transport on site, the withdrawal and injection members can be fixed in a removable manner or not on a frame independent of that of the conveying device. In this case, the two frames are placed end to end during operation so that the conveyed snow can be delivered by the picking member.

The operation of the arrangements described above is obvious and does not require a more detailed description. It goes without saying that, without departing from the scope of the invention, modifications can be made to the embodiments which have just been described.

Claims (19)

1. A method of pneumatically transporting snow intended for snow-making or snow-clearing operations comprising at least one power source driving an air generator, a member for injecting snow into the transport pipe producing a mixture of air and of snow, a removal member, drive means for driving said members linked to or independent of said power source, characterized in that said injection and removal members are in a stationary position, and in that a pile of snow is moved towards said sampling member, with a view to being debited there, by a conveying means according to a controlled translation speed and thickness. 2. Method according to claim 1 characterized in that the conveying means belongs to a group comprising the means with step by step movement and with continuous movement. 3. Method according to one of claims 1 and 2 characterized in that said speed of translation of the snow mass is controlled as a function of the resistive power acting on the sampling member in order to maintain said constant or lower power at a specific value. 4. Method according to one of claims 1 to 3 characterized in that said translation speed is controlled as a function of the resistant pneumatic power acting on the air generator in order to maintain said pneumatic power constant or less than a determined value . 5. Method according to one of claims 1 to 4 characterized in that the control of the translation speed is obtained by servo means acting in all or nothing. 6. Method according to one of claims 1 to 4 characterized in that the control of the translation speed is obtained by servo means acting by permanent action according to progressive and continuous values or according to discontinuous values by level. 7. Method according to claim 1 characterized in that the means for controlling the thickness of the snow mass are fixed. 8. Method according to claim 1 characterized in that the means for controlling the thickness of the snow mass are adjustable. 9. Device for implementing the method according to one of claims 1 to 8, comprising at least one power source driving an air generator, at least one snow injection member associated with a transport pipe producing a air and snow mixture, at least a withdrawal member, drive means for driving said members linked to or independent of said motor source, characterized in that said injection and withdrawal members are stationary and in that it further comprises a means of conveying moving in translation the snow heap towards the removal member and a clipping device having the function of controlling the thickness of the snow heap reaching the removal member. 10. Device according to claim 9, characterized in that the means for conveying the snow mass consists of a conveyor belt equipped with transverse spikes in order to drive the snow mass and drive means for said conveyor belt. 11. Device according to claim 9, characterized in that the means for conveying the snow pile consists of transverse spikes in order to entrain snow, sliding on a fixed floor, driven by two side chains actuated by means engines. 12. Device according to one of claims 9 to 11, characterized in that the clipping device consists of a conveyor belt driven by motor means whose median plane is inclined backwards, equipped with scraper spikes, the base of which is located in front of the removal member at a height which can be adjustable not exceeding that of the removal member and the direction of movement of which is opposite to that of the conveying device. 13. Device according to one of claims 9 to 11, characterized in that the clipping device consists of scraper-transverse spikes, fixed to two chains or side cables driven by motor means, whose median plane is inclined towards the rear, the base of which is located in front of the removal member at a height that can be adjustable not exceeding that of the removal member, and the direction of movement of which is opposite to that of the conveying device. 14. Device according to one of claims 9 to 13, characterized in that said snow removal and injection members are removably fixed to the frame receiving the conveying device in order to be able to use them separately on a vehicle. 15. Device according to one of claims 9 to 13, characterized in that said snow removal and injection members are permanently fixed to the frame receiving the conveying device. 16. Device according to one of claims 9 to 14, characterized in that the snow removal and injection members are fixed on a frame independent of that receiving the conveying device, the two frames being juxtaposed during operation in order to bring the snow conveyed onto the picking member. 17. Device according to claim 9, characterized in that it is extended lengthwise by at least one additional conveying means. 18. Device according to claim 9, characterized in that the injection member, the withdrawal member, the conveying means and the clipping device are fixed on a sledge. 19. Device for the pneumatic transport of snow, characterized in that it comprises several devices according to claim 9, associated transversely one next to the other.

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