Patent Grant
12332039
The present invention relates generally to the field of avalanche control systems, and more particularly, to a remote-controlled avalanche triggering apparatus that incorporates a tower and a detonation chamber that are joined together with a plurality of isolator springs.
Avalanches pose a risk to people and property. Avalanches have the ability to injure and kill people and cause significant and costly damage to property. An avalanche hitting an open highway or rail system can close transportation corridors and have financial impacts in the millions of dollars. The present invention aims to minimize avalanche risk to people and property by creating avalanches in an intentional and controlled manner and in predetermined locations. Solutions to the problem of unanticipated avalanches include both assessment and mitigation of avalanche risk. The present invention does not deal with the assessment of risk; it deals with mitigation of an identified risk.
Options that exist for avalanche mitigation include solid explosives, 105 mm high explosive (HE) howitzer rounds, skier-initiated avalanches a/k/a “ski cuts,” passive defense (such as constructing avalanche dams, ditches, earth mounds, and terraces or employing methods such as reforestation and architectural streamlining), and Remote Avalanche Control Systems (RACS). RACS are designed to minimize exposure to the individual operating the system by using communication technology that creates distance between the operator and the point of avalanche initiation. RACS are further divided into two categories: solid explosive-based and gas-based systems. In some cases, the use of solid explosives for avalanche mitigation is not possible. Some reasons for this include Bureau of Alcohol, Tobacco. Firearms and Explosives (ATF) regulations, land management agency restrictions, proximity to infrastructure, and inability to store solid explosives. The present invention is a gas-based system that utilizes gas explosions to trigger avalanches. Although there are other gas-based systems currently in use, the present invention has several unique characteristics that make it attractive to potential users and distinguishable from the prior art.
U.S. Pat. No. 6,279,481 (Schippers, 2001) provides a device for provoking the collapse of a snow cornice comprising several exploders, each of which has a main cylinder that is perpendicular to a support base arranged flat on the ground and a positioning tube that is connected to the main cylinder and mounted on a rigid seat fixed to the mountain side. Supply conduits are configured to deliver oxygen, propane, and a detonating gas mixture into a positioning tube and then into the main cylinder. Igniting means, which are mounted upstream of the supply conduit, are configured to ignite the detonating gas mixture.
U.S. Patent Application Pub. No. 2012/0318159 (Constant et al.) discloses an avalanche-inducing device that is comprised of a tube, one closed end of which is mounted onto a holder in the form of a concrete mass that is attached to a mountainside. The other end of the tube is open and is rotated toward the snow cover. The device includes a means for filling the tube with an explosive gas mixture and a priming means for inducing an explosion. The device has two beams that are attached on one end to the holder and that extend along the tube parallel to it. These beams are intended to absorb the movement of the tube following explosion of the gas mixture.
U.S. Patent Application Pub. No. 2006/0254449 (Hisel) describes an apparatus and method for avalanche control in which two gases are combined to form a detonable mixture that is detonated near an avalanche start zone. The gases are supplied at pressures above ambient pressure in order to drive them through a mixer and deploy the gases in the form of a detonable cloud in open air near the start zone. An igniter is situated in proximity to the discharge point of the detonable cloud and in communication with a controller that fires the igniter based on predetermined time intervals. The explosive gas mixture is detonated in open air.
U.S. Pat. No. 5,107,765 (Schippers, 1992) involves a process and device for triggering an avalanche. The device consists of a rigid explosion tank with a closed rear end and a front opening. The tank is mounted in the direction of the slope on which the avalanche is to be triggered. The tank is connected to sources of fuel gas and oxygen, which are delivered into the tank via injection nozzles and which combine to form an explosive mixture. The individual components of the explosive mixture are delivered to the tank at a pressure above atmospheric, and they achieve atmospheric pressure when combined within the tank. An ignition device is mounted in the bottom of the tank and operated via remote control.
U.S. Pat. No. 6,374,717 (Schippers, 2002) provides a device for provoking an avalanche that is comprised of a gas gun, one end (the upstream end) of which is pivotally attached to a seat that is solidly anchored to the mountain. The other end of the gun is supported by a leg that is configured to hold the downstream end of the gun above the level of the snow cover. The leg is preferably hollow and contains ballast consisting of chippings or concrete. The upstream end of the gun is equipped with ignition mechanisms (spark plugs) that are configured to discharge the device.
U.S. Pat. No. 5,864,517 (Hinkey et al., 1999) discloses a pulsed combustion acoustic wave generator comprised of an elongate tubular barrel with an inlet end and an open outlet end, a fuel controller that is configured to dispense a controlled quantity of fuel into the inlet end of the barrel, an oxidant controller that is configured to dispense a controlled quantity of oxidant into the inlet end of the barrel, and an igniter. The igniter extends into the inlet end of the barrel and is controllable by an operator. During operation, the generator produces sequentially pulsed directed pressure waves of sufficient pressure to incapacitate individuals at whom the open end of the barrel is pointed while minimizing effects on the operator of the generator, provided that the operator is not in the direct path of the pressure waves. As described by the inventors, this device may be used to trigger avalanches.
U.S. Patent Application Pub. No. 2013/0133543 (Farizy et al.) describes a device for setting off an avalanche comprising a support that is affixed to a concrete slab and an enclosure with an open end that faces the snow cap. The invention includes means for filling the enclosure with an explosive gaseous mixture, firing means, and a remote-communication system. The enclosure is removably mounted on the support and carries both the firing means and the means of storing the gases that are used to form the gaseous mixture.
The present invention is an avalanche triggering apparatus comprising: a tower having a first end, a second end, and a top part, the first end of the tower being connected to a base, and the top part of the tower being connected to a detonation chamber, two gas supply lines that are configured to deliver fuel gas and an oxidizer to the detonation chamber; a spark plug that is configured to initiate combustion of gases within the detonation chamber when activated by a flow switch; a battery that is configured to provide electricity to the spark plug; and means for controlling remotely a flow of gas through the gas supply lines; wherein the detonation chamber is connected to the tower via mounting brackets and a plurality of isolator springs; wherein the detonation chamber comprises a closed top end and an open bottom end; and wherein the open bottom end of the detonation chamber is configured to face a snow surface. In a preferred embodiment, the tower is comprised of at least two sections that are secured together via flanges. The invention preferably further comprises a ladder that is situated along the height of the tower and a handrail that is situated at a top of the ladder.
In a preferred embodiment, the detonation chamber is cylindrical in shape, and the tower is also cylindrical in shape with a constant outer diameter from top to bottom. Preferably, the second end of the tower is covered by a cover plate with an overhanging lip. The detonation chamber is preferably at a 15-degree angle relative to the top part of the tower.
In a preferred embodiment, the top of the detonation chamber is rounded so as to prevent snow and ice from accumulating on the top of the detonation chamber. In another preferred embodiment, the detonation chamber comprises at least one lifting bracket that is configured to facilitate lifting and transport of the detonation chamber, and the top end of the tower comprises at least one lifting bracket that is configured to facilitate lifting and transport of the tower.
In a preferred embodiment, a first mounting bracket is attached to the top part of the tower and is comprised of two side members and a front plate; wherein the two side members of the first mounting bracket are attached to opposing sides of the top part of the tower, and the front plate of the first mounting bracket extends across a front of the top part of the tower and connects the two side members of the first mounting bracket; wherein a second mounting bracket is attached to the detonation chamber and is comprised of two side members and a front plate; wherein the two side members of the second mounting bracket are attached to opposing sides of the detonation chamber, and the front plate of the second mounting bracket extends across a back of the detonation chamber and connects the two side members of the second mounting bracket; and wherein the front plate of the first mounting bracket and the detonation chamber are at a same angle relative to the tower. Preferably, a first pair of isolator springs is situated in between the front plate of the first mounting bracket and the front plate of the second mounting bracket on a first side of the first and second mounting brackets, and a second pair of isolator spring is situated in between the front plate of the first mounting bracket and the front plate of the second mounting bracket on a second side of the first and second mounting brackets; and each isolator spring is comprised of a helical cable isolator that is inserted through a plurality of holes in two aluminum members in a helical configuration. Each isolator spring is preferably configured to provide one inch of movement at a pull force of 4000 pounds.
In a preferred embodiment, each of the two gas supply lines connects to the detonation chamber at a pipe union; wherein each of the two pipe unions comprises a check valve; and wherein each of the two pipe unions is slanted downward so as to prevent snow or sleet that blows up into the detonation chamber from entering the gas supply lines. Preferably, the invention further comprises an ignition box that is situated on an inside wall of the top part of the tower; wherein the ignition box contains the battery, at least one capacitor, a voltage converter, and at least one terminal block. The flow switch is preferably configured to be activated by the flow of fuel gas from one of the two gas supply lines.
Highway departments, ski resorts, railways, utility companies and mining operations all have a need to create avalanches in areas that expose people and property to avalanche risk. The present invention is a RACS that uses a mixture of gases to produce an air blast at the snow surface. The gas is delivered to and mixed within the detonation chamber part of the exploder and is ignited using a spark. The resulting explosion creates a shockwave that produces a pressure wave. This pressure wave is typically strong enough to initiate a fracture of the slab within the snowpack. When conditions are prime for triggering, the pressure wave creates an avalanche. Because of this conditional relationship between the snowpack and the exploder, assessment and prediction is critical to the success of the effects of the exploder. In other words, the exploder does not create avalanches on command but rather requires the operator to understand the proper timing of conducting mitigation work and creating avalanches.
Traditional (non-RACS) methods of avalanche triggering involve transport, delivery and detonation of solid explosives by individual avalanche workers. This is typically accomplished on foot/skis or from helicopters. Although this method is widely used, it is time-intensive and exposes the avalanche worker to risk of injury. With the present invention, the risk to workers is minimized, and avalanches are created more efficiently. The exploder is controlled by the operator from a safe distance.
The present invention has five main component parts. These parts include the tower, the detonation chamber, the spark/igniter, gas supply, and gas management/delivery. The tower is permanently installed via a concrete base that is anchored to the ground. The detonation chamber is attached to the tower, and the spark/igniter is threaded into the detonation chamber. The gas management/delivery system is a series of hoses, valves, regulators and electronic controls that run between the gas supply and the exploder. The details of the present invention are discussed more fully below.
Extending vertically upright from the base is the tower 2. The tower 2 may be comprised of one or more sections that are secured together via flanges 3. By installing the tower 2 in sections via flanges 3, the overall height of the tower 2 can be adjusted as necessary for a given installation. A ladder 4 is disposed along one side of the tower 2. The ladder 4 may be comprised of one or more sections, as shown. The top of the ladder 4 preferably comprises a handrail 5 that is configured to support a person who has climbed to the top of the ladder.
The detonation chamber 6 is positioned at the top of the tower 2 and attached to the tower with a pair of mounting brackets 7 that are connected to each other via four pairs of isolator springs 15. The detonation chamber 6 is preferably cylindrical in shape.
The mounting brackets 7 and isolator springs 15 are discussed in further detail in connection with
Gas supply lines 11 are configured to deliver oxygen and a combustible gas to the detonation chamber 6. A cover 12 in the form of a box is situated on the exterior of the detonation chamber 6 houses the spark plug (see
The isolator springs 15 are intended to absorb the forces created by an explosion in the detonation chamber 6, thereby prolonging the overall life of the system. Specifically, the isolator springs 15 help to minimize the strain on the tower itself. Over time, the impact of the explosions will degrade the connection between the tower and the detonation chamber, at which point the detonation chamber can be removed and replaced. The detonation chamber is removed by removing the bolts that secure the isolator springs 15 to the first mounting bracket 7a and lifting the detonation chamber by helicopter.
In the particular configuration shown in
The tower and detonation chamber are installed in an avalanche starting zone. The tower is attached to anchor bolts, which are permanently fixed into the concrete base. The concrete base is prepped and poured onsite, typically in remote and rugged mountainous terrain.
The detonation chamber is fixed to the tower at an angle of fifteen (15) degrees and points down towards the snow surface. Between the detonation chamber and the tower is a series of shock absorbing coils/isolator springs that help to minimize the strain on the tower itself. Over time the impact of the explosions degrades the connection between the tower and the detonation chamber. When this happens, the detonation chamber can be replaced while the tower remains in place.
Gas cylinders (some combination of oxygen, methane and hydrogen) are stored separately and within a reasonable distance (no closer than 30 meters and up to a kilometer) from the tower/detonation chamber. The cylinders are placed in a standard rack and anchored to the ground or a man-made surface (wooden, steel or concrete deck). A series of hoses and regulators are situated between the gas supply and the tower/detonation chamber. Hoses from the gas management system to the detonation chamber are preferably ½″ polyethylene (PE) pipe. These pipes will be run inside of a conduit that is appropriate for the terrain. The conduit can be a thick wall, large diameter PE pipe for buried sections or for use in areas above ground where there is little to no chance of the pipe being damaged. Where the conduit must be run above ground and damage is likely, steel pipe or rigid polyvinyl chloride (PVC) pipe must be used. The gas cylinders attach to high-pressure gas lines with the appropriate fittings. The gas lines are then interrupted by a series of regulators that control the volume of gas being delivered through the system. The gas lines terminate at and are threaded into the detonation chamber.
This system has the ability to employ a vertical distance of five hundred (500) meters and a horizontal distance of one kilometer between the gas supply and the tower/detonation chamber. This is a unique feature of the system and has the potential to greatly reduce user costs. By having longer gas line runs, the location options for gas storage change from remote terrain only accessible by helicopter to locations closer to roads, trails and rail systems. By increasing location options, the user can potentially use wheeled and/or over-snow vehicles to resupply gas.
A mixture of gases is delivered to the detonation chamber. The mixtures that have been used by the inventors in testing the present invention thus far are oxygen/methane and oxygen/hydrogen; the present invention is not limited to any particular gas mixture, however, as long as it is ignitable. Once the proper mixture and volume of gas is achieved within the detonation chamber, a spark is initiated and creates an explosion of the gases. The spark is achieved through a flow switch, as noted above.
The ignition system uses a gas flow switch with a set of single pole double throw (SPDT) contacts. The common contact connects to a 10,000 uF capacitor, the normally closed (NC) contact connects to a spark generator, and the normally open (NO) contact connects to a battery. When gas flow starts, the flow switch detects the pressure increase and closes the connection between the battery and the capacitor. When the flow stops, the pressure drops, and the capacitor discharges into the spark generator, which sends high voltage to a spark plug, thereby igniting the gas mixture. This system is designed to optimize the detonation timing. It is imperative that the gas mixture ignites immediately after gas flow stops; this timing ensures that the oxygen and methane are still mixed evenly in the detonation chamber, allowing for optimal explosion velocity.
In the event of a misfire, the system is purged using nitrogen. This is done on a ten-minute cycle. After the system is purged, the user can safely troubleshoot the system without risk of detonation.
Snowpack assessment and avalanche forecasting require the user/operator to have a well-developed understanding of snowpack structure, fracture mechanics and meteorological influences on the snowpack. The user/operator is responsible for understanding when the time is right for attempting to trigger an avalanche and for deciding which mitigation efforts to employ. The present invention is designed to be used when the user/operator deems the snowpack unstable and capable of releasing avalanches from the trigger point.
There are four factors that must be present for an avalanche to occur: (i) a slab; (ii) a weak layer; (iii) terrain steep enough to produce avalanches; and (iv) a trigger. When the overlying slab or the underlying weak layer or both are at a critical point, the user introduces a trigger such as an air blast to create avalanches. The overpressure values created by gas-based systems have proven to be effective in generating avalanches. It is important to install the exploder in the best location possible for avalanche initiation. This process involves detailed terrain analysis, as well as snowpack and weather history. The pressure wave that is emitted from the detonation chamber creates enough impact on the snow (slab and weak layer) to initiate an avalanche.
The present invention has numerous advantages over the prior art. The gas management system of the present invention is kept unpressurized to minimize the potential of leaks. In addition, there are fewer component parts than in existing RACS, which results in a less complex system with fewer potential fail points. A major complaint of other gas-based systems by users/operators is the prevalence of leaks within the system. Pressurized gas contained within lines and passing through a series of metal fittings tends to leak when subjected to wide temperature swings. Some mountainous locations where the present invention may be installed might experience temperature swings of 100 degrees Fahrenheit over the course of a year.
The present invention also incorporates longer gas lines than in conventional avalanche control systems. With the present invention, operators have the ability not only to run gas lines uphill but also to run them for long distances, thereby reducing dependence on helicopters, increasing reliability, and decreasing operating costs. Initial testing has shown the potential to run lines up to 1 km in horizontal distance and 500 m in vertical rise. This flexibility allows users to install the gas supply in areas that are less expensive to access and to eliminate the use of a helicopter altogether.
The present invention also affords the user the ability to utilize different gas mixtures to create desired effects. Deeper snowpacks are generally safer than shallower snowpacks. The present invention enables the user to produce different shock waves to target the specific avalanche problem without wiping a slope clean. When repeatedly triggering avalanches in the same location over the course of the season, the snowpack immediately below the detonation chamber has the potential to remain shallow. When subjected to air and snowpack temperature swings, the snowpack is subjected to weakening due to a change in vapor pressure. This change is commonly referred to as a temperature gradient. When this steep gradient is present, vapor moves through the snowpack and recrystallizes at layer boundaries. This recrystallization allows for the formation of faceted snow grains, which are structurally weak. By themselves, facets do not pose a problem, but when overloaded by new snow in the form of slabs, the faceted layer of snow then becomes a weak layer that can fail more readily. By giving users the option of changing the peak and overall pressure on the snowpack through different gas mixtures and volumes, the user can decide how deeply to impact the underlying snowpack.
Although the preferred embodiment of the present invention has been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. The appended claims are therefore intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5107765 | Schippers | Apr 1992 | A |
| 5864517 | Hinkey et al. | Jan 1999 | A |
| 6279481 | Schippers | Aug 2001 | B1 |
| 6374717 | Schippers | Apr 2002 | B1 |
| 7707938 | Hisel | May 2010 | B2 |
| 8904939 | Constant | Dec 2014 | B2 |
| 8960092 | Farizy | Feb 2015 | B2 |
| 12007218 | Berthet-Rambaud | Jun 2024 | B2 |
| 12078466 | Rivoal | Sep 2024 | B2 |
| 20060254449 | Hisel | Nov 2006 | A1 |
| 20120318159 | Constant et al. | Dec 2012 | A1 |
| 20130133543 | Farizy et al. | May 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| 713422 | Nov 2021 | CH |
| WO 2021069839 | Apr 2021 | WO |
| WO 2021255370 | Dec 2021 | WO |
| WO 2022258930 | Dec 2022 | WO |
| Entry |
|---|
| The Gazex Avalanche Release System, Schippers, J et al. Source: Published in: International Snow Science Workshop 2002: 46-48 Publication Date: Sep. 1, 2002. |
| International Search Report and Written Opinion in PCT/US25/10697; dated Mar. 7, 2025. |
| “Alta Ski Area” (UTAH) Jul. 9, 2023; cited in ISR/WO. |
| “Using gas explosions to trigger avalanches remotely” (INSTAGRAM) Jan. 23, 2024; cited in ISR/WO. |
| “Wire Rope Isolators for Vibration Isolation” (ENIDINE) Sep. 22, 2023; cited in ISR/WO. |
