Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42D—BLASTING
  • F42D3/00—Particular applications of blasting techniques

Definitions

• the invention relates to a method of artificially triggering an avalanche and more generally to a method of artificially triggering a natural phenomenon in which one or more explosions of a fluid are caused in a predetermined area where the we want to trigger this phenomenon.
• the invention can be applied in all fields where a phenomenon can be caused or set in motion by a local overpressure of the atmosphere above the zone concerned by the phenomenon.
• the field targeted by the invention is the artificial triggering of snow avalanches in winter sports resorts and on sites presenting a potential risk for people, ski areas, ski lifts, roads and routes. access, mountain railways and, in general, public and private constructions and facilities.
• the invention also relates to a device for implementing this process comprising means for causing at least one explosion of a fluid in a predetermined area where it is desired to trigger said phenomenon.
• one of these means consists in placing or launching explosive charges such as TNT and in causing the explosion of these charges.
• the explosion causes a breath that sweeps the surface of the snowpack in the avalanche area, and a shock wave that shakes the base of this snowpack and triggers an avalanche.
• a device comprising a barrel, or metal tube, having a closed bottom, and an open front mouth in the direction of the snowpack.
• This device also includes a circuit for supplying oxidant gas from a first source and a circuit for supplying fuel gas from a second source.
• Nozzles for filling the barrel with these gases are arranged in various zones distributed over the length of this barrel and an ignition device is mounted at the rear of the barrel.
• a gas mixture is formed inside the barrel, for example a mixture of propane and oxygen, and the explosion of this mixture is caused in the barrel by the ignition device.
• the frontal mouth of the gun diffuses the breath and the shock wave caused by the explosion on the surface of the snowpack thus triggering the avalanche.
• the present invention specifically aims to overcome the aforementioned drawbacks by providing a method of artificially triggering an avalanche by at least one explosion of an explosive fluid in a predetermined area, said method comprising a first step of filling at least a flexible envelope with an explosive fluid and a second step of triggering an explosion of said fluid inside each envelope, each envelope being destroyed by the explosion of the fluid that it contains.
• the fluid can be introduced into the envelope by means of a diffuser, the diffuser being connected to a gas source by means of a gas supply pipe.
• the flexible envelope can be fixed directly to the diffuser which can then serve as a fixed support for the flexible envelope during its filling.
• the fluid can be an explosive gas mixture of an oxidizer and a fuel.
• a combustible gas is used as the gaseous fuel.
• This combustible gas can be chosen from the group of substances comprising hydrogen, tetraine, acetylene, propane, butane, or a mixture of these substances, preferably hydrogen.
• the oxidizer used can be oxygen or ozone, air, or air enriched with oxygen or ozone, preferably air.
• the fluid inside each flexible envelope can be at a pressure equal to or substantially higher than atmospheric pressure when the envelope
• each flexible envelope used must be made of a material which can be destroyed by the explosion of the fluid which it contains.
• the material constituting the flexible envelope and the thickness of this material must in fact be chosen so as to release the overpressure wave created by the explosion of the fluid which it contains, without opposing too much resistance to this explosion. .
• This material must also be able to contain the fluid until the latter is exploded and therefore have a certain seal.
• the flexible envelope can be made of a light material in such a way that for a gaseous mixture forming a fluid lighter than the surrounding air, for example an explosive mixture of hydrogen and d 'air, the envelope is maintained in vertical position above the snowpack.
• this envelope may advantageously be biodegradable so as not to pollute the environment.
• An example of a flexible envelope having all the characteristics mentioned above is an envelope made of a material chosen from the group comprising butyl.
• the thickness of the material constituting the envelope may for example be approximately
• the envelope may for example be a meteorological type balloon.
• This flexible envelope must moreover have a volume such that it can contain a sufficient volume of fluid, at atmospheric pressure or at a pressure slightly higher than this, so that the explosion of this fluid makes it possible to trigger the avalanche.
• the minimum volume of the envelope can be determined by the following reasoning, considering that the fluid in the enclosure is at atmospheric pressure:
• Equation (I) is the chemical equation for the explosion of the H 2 / oxygen mixture in the air: This equation (I) shows that the stoichiometric mixture of the explosion under normal conditions of temperature and pressure (273 ° Kelvin, and
• 101 325 Pa includes two volumes of H 2 for one volume from 0 2 .
• the fluid is a hydrogen / air mixture
• this corresponds to 30% hydrogen by volume and 70% air by volume.
• the explosion of 2 g of H 2 (1 mole of H 2 ) according to equation (I) providing 57,800 calories, or approximately 60,000 calories, and the explosion of 1 g of TNT providing 1,000 calories, 1 g of H 2 is equivalent to 30 g of TNT in potency.
• the density of hydrogen being 90 g / m 3 , 1 m 3 of hydrogen is equivalent to 2700 g of TNT. Considering that for various reasons such as the quality of the gas mixture, the temperature, etc.
• 1 m 3 of hydrogen can provide an energy equivalent to the explosion of 1.35 kg of TNT. It is therefore preferable to use a volume of hydrogen of 2.2 m 3 so that the detonation power is sufficient, that is to say equivalent to the explosion of 3 kg of TNT, to trigger the avalanche. This volume of hydrogen requires an air volume of 6.8 m 3 to obtain a detonating stoichiometric mixture.
• the minimum preferable volume of the enclosure for an H 2 / a ⁇ r mixture is therefore 8.9 m 3 when the fluid filling the enclosure is at atmospheric pressure.
• the volume of the envelope is therefore chosen in adequacy with a volume of explosive fluid sufficient to trigger an avalanche and therefore also according to the nature of this fluid.
• the second step of the method is a step of triggering an explosion of the fluid inside each envelope.
• This explosion can be triggered by conventional means of triggering an explosion making it possible to generate a spark in each enclosure.
• These means may include, for example, a primer head, a piezoelectric device, a lighter stone, etc.
• the explosion of the fluid contained in each envelope causes its destruction and the propagation of a spherical air wave pressure which will interest an optimal surface of the snowpack, function of the volume of the explosive fluid in the enclosure before the explosion, and will shake said surface by triggering an avalanche.
• the flexible envelope (flexible envelopes) is
• This envelope (these envelopes) is (are) fixed (s) by means of a support which does not interfere with the propagation of the breath and of the shock wave created by the explosion of the fluid above said predetermined zone for example at a distance ranging from 2 to 3 m from the surface of the snowpack for an envelope (envelopes), having a volume of 10 m 3 , filled with an explosive mixture of hydrogen and air.
• each flexible envelope can be folded into a container corresponding, the step of filling this envelope then comprises a deployment phase of said envelope outside of said container.
• the container must be made of a material resistant to the explosion of the fluid contained in one of the envelopes when several envelopes folded into several corresponding containers are provided.
• each container can be closed by a cap, the step of filling the corresponding envelope then comprises a phase of ejection of said cap so as to allow the deployment of the envelope.
• the cap can be ejected for example by the pressure exerted by the fluid inside the flexible envelope folded back into the container during the first step of filling said envelope with the fluid.
• This cap may be biodegradable so as not to pollute the environment, or remain fixed to the container so as not to hinder the deployment of the envelope outside said container.
• the step of filling each envelope may further comprise a phase of suction of the ambient atmospheric air and of mixing this air with a suitable gas so as to form the explosive fluid .
• the suitable gas can be chosen from the group comprising hydrogen, helium, tetraine, acetylene, propane, methane, etc. or a mixture of these gases.
• the air can for example be drawn from the atmosphere and mixed with the gas (es) by means of a vacuum system of the venturi type called hereinafter the venturi system to be introduced into the envelope, the appropriate gas passing through the venturi under pressure, entraining ambient air by vacuum.
• the venturi system can be chosen in such a way that for a given flow of gas passing through it, the air / gas mixture formed, at the outlet of this venturi, is an explosive mixture. In this way, the mixing is carried out automatically by the venturi to be introduced into the enclosure.
• a single reserve of gas for example hydrogen
• this process does not require a gas mixing tank unlike to the process described on page 2, lines 17 to 32 and includes reduced hydraulic equipment, a single gas pipe connecting the reserve to the device being necessary.
• venturi system optimizes the efficiency and reproducibility of the explosive mixture. It is also a simple, static system that does not require sophisticated technology, has few components and therefore has a low cost.
• the fuel can be hydrogen, since the air / hydrogen mixture formed has a relatively wide explosive mixture range in hydrogen concentration, that is to say ranging from 13.5% by volume to 59% by volume. volume, with a maximum detonation wave pressure at 32.5% hydrogen by volume, allowing imprecise mixing, therefore not requiring any particular measuring device such as a flow meter.
• the diffuser on which the enclosure can be fixed can comprise the venturi system.
• the introduction of the fluid into one of the envelopes and the explosion of the fluid in said envelope can be controlled by an automatic incrementing system.
• This automatic incrementing system makes it possible to control the first and second stages which are linked, for each envelope, successively, until all the envelopes provided have been used.
• the invention also relates to a device for implementing the method of the invention.
• This artificial triggering device of an avalanche by at least one explosion of an explosive fluid in a predetermined area comprises at least one envelope intended to contain the fluid, means for filling each envelope with the fluid, means for triggering the explosion of this fluid in each envelope and means for controlling the filling of each envelope and for triggering each explosion, each envelope being constituted of a material such that it is destroyed by the explosion of the fluid which it contains.
• the fluid can be an explosive mixture of atmospheric air and at least one gas, said filling means then comprise means for aspirating ambient atmospheric air.
• the means for aspirating ambient atmospheric air can be vacuum-type pressure-reducing systems.
• the flexible envelope consists of a material chosen from the group comprising butyl.
• a meteorological type envelope with a volume of 10 m 3 .
• the means for triggering the explosion in the envelope may comprise a primer head placed in the envelope, in contact with the fluid that it contains.
• the device can further comprise a container for each envelope, said envelope being folded back into the corresponding container when it is empty, so that it can come out of said container and deploy when the fluid is introduced into the envelope.
• each container may further comprise an ejectable cover during the introduction of the fluid into the envelope.
• the corresponding ejection containers and cover are advantageously made of a material capable of withstanding the atmospheric overpressure due to the explosion of the fluid in one of the balloons.
• This material is for example chosen from the group comprising polypropylene, for the container, and for the ejection lid.
• the device when the device comprises several containers, they can be fixed on a support anchored to the ground.
• this support may include a first removable part on which the containers are fixed and a second fixed part anchored to the ground.
• the removable part must be able to be fixed on the fixed part in such a way that its position on the fixed part is not modified by the explosion of the envelopes.
• the removable part of the support can be replaced, when all the envelopes have been used by a new removable part on which are fixed new envelopes and corresponding containers.
• a removable part comprising envelopes of a certain volume can be easily replaced by another removable part comprising envelopes of a different volume.
• anchoring to the ground does not require an anchor concrete block, rapid anchoring means such as anchoring by explosive piles are sufficient.
• the device according to the invention can therefore be easily transportable, due to the presence of a removable part and of a part fixed to the ground by a quick anchorage, and can in certain cases avoid helicopter transport to be moved.
• the fixed part and / or the removable part can be adjustable in height so as to be able to respond to multiple locations of the device of the invention.
• the device Preferably, the device must be as compact as possible for good integration into the site, good resistance to winds and snow crawling.
• the second fixed part may include a distributor for distributing gas in each envelope, means for controlling the filling of each of the envelopes, and means for controlling the explosion of the fluid in each of these envelopes.
• the device can include an increment control system for filling and exploding the fluid in each of the envelopes successively.
• the device may preferably comprise means for remote control of the means for filling each of the envelopes and for exploding the fluid in each of these envelopes.
• each container can be of cylindrical shape and can comprise a first end formed by a bottom and a second end formed by an ejectable cover, said cover being of conical shape.
• the bottom of the container can be crossed by a gas supply pipe, said pipe being able to pass through the cylindrical container substantially along its axis of symmetry, and ending at the conical cover by a diffuser on which can be fixed the envelope, said diffuser being intended to introduce the fluid into one envelope.
• the diffuser may comprise a venturi system, comprising a lateral orifice for aspiration of atmospheric ambient air, said orifice being preferably located at the level of the conical cover so as to facilitate the aspiration of air.
• the support can support 10, 15, 20 or 25 containers depending on the frequency of triggering of avalanches envisaged in a winter season.
• the gas is preferably hydrogen.
• the device according to the invention preferably comprising several envelopes, is located in a predetermined area corresponding to a starting area of an avalanche.
• the device of the invention can be connected to a control station preferably placed at a distance from the device according to the invention, that is to say in a non-avalanche zone.
• This control station can comprise, for example, the storage of gas, for example hydrogen, an electronic control system of the device according to the invention, a transmitter / receiver for remote control of the control station, and a battery device. and solar panels to provide power.
• the device according to the invention has many advantages such as reduced volume and weight, great mobility, good integration into the landscape, a reduced control and gas reserve station, reduced hydraulic equipment, an explosive mixture automatically obtained stoichiometric, minimum cost price, high efficiency and great respect for the environment.
• FIG. 1 is a diagram of the device according to the invention illustrating an envelope filled with the explosive fluid
• FIG. 2 is a diagram of an enlargement of a cross section of a diffuser comprising a venturi system on which is fixed an envelope;
• FIG. 3 is a cross-sectional view of an embodiment of the device of the present invention comprising several containers and corresponding envelopes, showing in cross-section a container in which an envelope is folded;
• - Figure 4 is a sectional view from above of the device according to the invention in which several containers are provided;
• - Figure 5 is a general diagram of a device according to the invention and its control station.
• the device shown essentially consists of an envelope 2, in the form of a meteorological balloon of butyl deployed, filled with a fluid 3 consisting of a mixture of hydrogen and air.
• This envelope 2 is fixed, by means of a collar 6 for maintaining the envelope, on a diffuser 5 intended to introduce the fluid into the envelope.
• the diffuser 5 is supplied with hydrogen at a pressure of 3 to 6 Bar by a pipe 7 for supplying gas, the supply of gas in this envelope being controlled by a solenoid valve 9.
• a container 11 in which the envelope was folded before being filled with the fluid, and an ejectable cover 13, which was ejected during the filling of the envelope with the fluid.
• the container 11 is fixed on a support 15.
• FIG. 1 is a diagram of an enlargement of a cross section of the diffuser 5 on which the casing is fixed 2.
• the diffuser 5 comprises a venturi system on which is provided a lateral orifice 17 for suction of ambient atmospheric air .
• This venturi system makes it possible to inject ambient atmospheric air into the envelope by suction, the flow of hydrogen under pressure in this system being the engine, so as to form the explosive fluid.
• the venturi system is chosen according to a hydrogen pressure of 3 to 6 Bar at the inlet of this system.
• the duct 7 for supplying H 2 through the diffuser is a suitable tube for supplying a gas having a diameter of approximately 30 mm.
• the hydrogen / air mixture formed comprises from 25 to 35% of hydrogen by volume and from 75 to 65% of air by volume.
• the wires 8 conducting electricity intended to supply the primer head 4 for triggering the explosion of the fluid in the envelope are also shown in this figure.
• Figure 3 is a cross-sectional view of an embodiment of a device 1 according to the present invention comprising several envelopes 2 folded in corresponding containers 11, showing in cross section a container 11 in which an envelope 2 is folded such that it can leave this container and deploy when the fluid is introduced into the envelope.
• Each container is cylindrical in shape and has a diameter of 60 to 80 mm.
• a cover 13, conical, ejectable closes each container 11 so as to protect the corresponding envelope until it is filled with the fluid.
• Port 17 lateral of each venturi system is located under the ejectable cover 13 so as to be able to easily aspirate atmospheric air when the hydrogen is injected through this system.
• the pressure exerted by the fluid in the envelope causes the cover 13 to be ejected so as to be able to leave the container and deploy.
• the containers are fixed on a support 15 forming a first removable part 19 of the device, said first removable part 19 being fixed on a fixed support 23, anchored to the ground 25, having a height from the ground of 1 to 2.5 m.
• Each container is supplied by a solenoid valve 9 having a temperature resistance of -20 ° C supplied with low voltage at 12 or 24 V. All the solenoid valves are grouped together on a single distributor 19 placed on the fixed support 23.
• the fixed support 23 also includes a distributor 27 for electrical control of the solenoid valves 9 and the primer heads in each casing (not shown) connected to each solenoid valve and to each primer head by means of an electric multi-conductor cable 29.
• This distributor 27 is carefully shielded by means of a metal box and grounded.
• the containers are assembled in the factory, this assembly comprises a fitting of a primer head in each envelope, an assembly and a fixing of each envelope on a diffuser, a folding of each envelope in each corresponding container and an assembly of '' a conical ejection lid on each container.
• Figure 4 is a sectional view from above of the removable support 19 on which are distributed in a circle
• Figure 5 is a general diagram of a device
• the control station 31 is located in the upper part with respect to the avalanche departure zone in which the device 1 is placed.
• the control station 31 is composed of a faradized heliport shelter 32 in the functional position. This shelter includes:
• a supply of electrical power necessary to operate the control means of the device according to the invention comprising two 12 V, 80 Ah, heat-insulated batteries, buffered with a solar panel 51, 24 V, 1000 W, placed on the shelter.
• an electronic control control cabinet comprising an interface between a transmitter / receiver 43 and a control means
• control means 45 for filling each envelope and triggering the corresponding explosion
• Each bottle has a volume of 50 1 and contains 9000 liters of hydrogen at a pressure of 180 Bar. This represents in total for 11 bottles a volume of 99,000 liters of hydrogen available at atmospheric pressure. Considering that the hydrogen is expanded to a pressure of 4 Bar for filling the envelopes, the available volume will be 176 x 50 x 11, ie 96,800 liters of hydrogen.
• envelope 2 having a volume of 10 m 3 with an explosive mixture of hydrogen and air, 2200 liters of hydrogen are used. This frame will therefore satisfy the filling of approximately 40 10 m 3 envelopes.
• the shelter is placed on the ground on a wire mesh, the ground plane being grounded and anchored. High and low vents, protected from snow and insects, are provided to prevent any accumulation of hydrogen in the shelter. The shelter is protected against intrusion by a locked door, not shown.
• Links are provided between the control station 31 and the device 1 according to the invention. These connections are a tube 33 for supplying hydrogen from the control station 31 to the device 1, and a cable 39 for transmitting control of the solenoid valves 9 and of the priming heads of each casing.
• the tube 33 is a medium pressure tube, sheathed by a metal tube for mechanical protection and shielding and anchored from time to time between the control station and the device 1 to prevent it from being torn off by the crawling of snow or scree.
• the shielding of this tube is connected to the mass of the shelter and to the mass of the device 1.
• the internal diameter of this tube is 8 to 10 mm in order to reduce the pressure losses over the length.
• the main solenoid valve 35 controls the supply of hydrogen from the control station to the device 1 through the tube 33, the single pressure regulator 37 HP / BP, 180/10 Bar making it possible to adjust a static pressure of hydrogen at the outlet of this pressure regulator, in tube 33, at 4 to 6 Bar.
• the static pressure at the outlet of the single pressure regulator 37 is adjusted along the length of the tube 33 between the control station and the device 1.
• the static pressure of hydrogen in the tube 33 and the rolling diameter of each solenoid valve 9 are decisive for the filling time of each envelope.
• This filling time is preferably 1 to 2 minutes to take account in particular of the wind, the friction of each envelope on the roughness of the device, etc.
• the cable 39 is a multi-pair cable, shielded, comprising mechanical and electrical protection. It comprises a number of pairs in relation to the number of envelopes provided on the device 1. Each pair is shielded.
• This cable 39 makes the electrical connection between the control station 31 and the distributor 27 for electrical control of the solenoid valves 9 and the primer heads, not shown, of each envelope.
• An electronic coding system allows automatic incrementation, of filling and explosion control, from a destroyed envelope to an envelope folded in a container.
• the transmitter / receiver 43 in the control station 31 is in permanent standby thanks to the electric power supply by battery and solar panel. It can be activated for example by radio control from a general control center in a ski slope service according to the following operating diagram:

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Electrotherapy Devices (AREA)
• Eye Examination Apparatus (AREA)
• Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)
• Manufacture, Treatment Of Glass Fibers (AREA)
• Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
• Prostheses (AREA)
• Examining Or Testing Airtightness (AREA)
• Processing Of Terminals (AREA)
• Ropes Or Cables (AREA)
• Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
• Manipulator (AREA)
• Surgical Instruments (AREA)
• External Artificial Organs (AREA)
• Control And Safety Of Cranes (AREA)
• Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
• Air Bags (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=9513431

Family Applications (1)

Country Status (12)

Cited By (3)

Families Citing this family (19)

Family Cites Families (9)

• 1997
  • 1997-11-17 FR FR9714366A patent/FR2771168B1/fr not_active Expired - Fee Related
• 1998
  • 1998-11-16 EP EP98955667A patent/EP1031008B1/de not_active Expired - Lifetime
  • 1998-11-16 JP JP2000521358A patent/JP4180794B2/ja not_active Expired - Fee Related
  • 1998-11-16 TR TR2000/01359T patent/TR200001359T2/xx unknown
  • 1998-11-16 DE DE69812150T patent/DE69812150T2/de not_active Expired - Lifetime
  • 1998-11-16 US US09/554,218 patent/US6324982B1/en not_active Expired - Lifetime
  • 1998-11-16 AT AT98955667T patent/ATE234457T1/de active
  • 1998-11-16 WO PCT/FR1998/002441 patent/WO1999026039A1/fr not_active Ceased
  • 1998-11-16 ES ES98955667T patent/ES2194364T3/es not_active Expired - Lifetime
  • 1998-11-16 CA CA002310113A patent/CA2310113C/fr not_active Expired - Fee Related
• 2000
  • 2000-04-27 IS IS5474A patent/IS5474A/is unknown
  • 2000-05-08 NO NO20002393A patent/NO318333B1/no not_active IP Right Cessation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events