Avalanche triggering apparatus

Abstract

An avalanche triggering apparatus having a tower, a detonation chamber, and gas supply lines that are configured to deliver fuel gas and oxidizer to the detonation chamber. The flow is gas is controlled remotely, and a spark plug is configured to ignite gases within the detonation chamber based on the flow of fuel gas through a flow switch that acts as a sensor. The detonation chamber has a closed, rounded top and an open bottom end that is configured to face a snow surface. The detonation chamber is connected to the tower via mounting brackets and two pairs of isolator springs. 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. The tower is comprised of at least two sections that are secured together via flanges.

Claims

1. An avalanche triggering apparatus comprising: (a) 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; (b) two gas supply lines that are configured to deliver fuel gas and an oxidizer to the detonation chamber; (c) a spark plug that is configured to initiate combustion of gases within the detonation chamber when activated by a flow switch; (d) a battery that is configured to provide electricity to the spark plug; and (e) 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.

2. The avalanche triggering apparatus of claim 1, wherein the tower is comprised of at least two sections that are secured together via flanges.

3. The avalanche triggering apparatus of claim 1, wherein the tower has a height, further comprising a ladder that is situated along the height of the tower and a handrail that is situated at a top of the ladder.

4. The avalanche triggering apparatus of claim 1, wherein the detonation chamber is cylindrical in shape.

5. The avalanche triggering apparatus of claim 1, wherein the second end of the tower is covered by a cover plate with an overhanging lip.

6. The avalanche triggering apparatus of claim 1, wherein the detonation chamber is at a 15-degree angle relative to the top part of the tower.

7. The avalanche triggering apparatus of claim 1, wherein the tower is cylindrical in shape with a constant outer diameter from top to bottom.

8. The avalanche triggering apparatus of claim 1, wherein the top of the detonation chamber is rounded so as to prevent snow and ice from accumulating on the top of the detonation chamber.

9. The avalanche triggering apparatus of claim 1, wherein 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.

10. The avalanche triggering apparatus of claim 1, wherein 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.

11. The avalanche triggering apparatus of claim 10, wherein 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 springs 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 wherein 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.

12. The avalanche triggering apparatus of claim 11, wherein each isolator spring is configured to provide one inch of movement at a pull force of 4000 pounds.

13. The avalanche triggering apparatus of claim 1, wherein 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.

14. The avalanche triggering apparatus of claim 1, further comprising 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.

15. The avalanche triggering apparatus of claim 1, wherein the flow switch is configured to be activated by the flow of fuel gas from one of the two gas supply lines.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a first perspective view of the present invention.

(2) FIG. 2 is a second perspective view of the present invention.

(3) FIG. 3 is a side view of the present invention.

(4) FIG. 4 is a top view of the present invention.

(5) FIG. 5 is a section view of the present invention taken at the line shown in FIG. 4.

(6) FIG. 6 is a section view of the detonation chamber and the top part of the tower taken at the line shown in FIG. 4.

(7) FIG. 7 is a perspective view of the detonation chamber and the top part of the tower.

(8) FIG. 8 is the same view as is shown in FIG. 7 but with the ladder, tower, cover plate, and one of the two mounting brackets removed.

(9) FIG. 9 is a detail view of the control box of the present invention.

(10) FIG. 10 is a detail view of the spark plug inside of the detonation chamber.

(11) FIG. 11 is a detail view of the isolator spring of the present invention.

(12) FIG. 12 is a detail view of the overhanging lip of the cover plate at the top of the tower.

REFERENCE NUMBERS

(13) 1 Base 2 Tower 3 Flange 4 Ladder 5 Handrail 6 Detonation chamber 6a Top end (of detonation chamber) 6b Bottom end (of detonation chamber) 7 Mounting bracket 7a First mounting bracket 7b Side member (of first mounting bracket) 7c Front plate (of first mounting bracket) 7d Second mounting bracket 7e Side member (of second mounting bracket) 7f Front plate (of second mounting bracket) 8 Cover plate 8a Overhanging Up (of cover plate) 9 Lifting bracket 10 Handle (of cover plate) 11 Gas supply line 12 Cover (for spark plug) 13 Electrical cable 14 Port (on base) 15 Isolator spring 15a Helical cable isolator (of isolator spring) 15b Aluminum member (of isolator spring) 16 Ignition box 17 Battery 18 Capacitor 19 Voltage converter 20 Terminal block 21 Pipe union 22 Signal wire 23 Flow switch 24 Grip handle Spark plug 26 Splice (in gas line)

DETAILED DESCRIPTION OF INVENTION

A. Overview

(14) 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.

(15) 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.

(16) 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.

B. Detailed Description of the Figures

(17) FIG. 1 is a first perspective view of the present invention, and FIG. 2 is a second perspective view of the present invention. As shown in these two figures, the invention is comprised of a base 1, which in a preferred embodiment is a concrete platform that is permanently secured to the ground via anchor bolts (not shown). The invention is installed in an avalanche starting zone, and the concrete base 1 is prepped and poured onsite, typically in remote and rugged mountainous terrain.

(18) 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.

(19) 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.

(20) The mounting brackets 7 and isolator springs 15 are discussed in further detail in connection with FIG. 7. The tower 2 has a closed bottom end (which abuts up against the base 1) and a closed top end that is covered by a cover plate 8. The cover plate preferably has a slightly greater diameter than the top of end of the tower 2 so that the cover plate forms an overhanging lip 8a (see FIG. 12); in this manner, the cover plate 8 is fully supported by the top end of the tower. The detonation chamber 6 comprises a closed top end 6a and an open bottom end 6b, and the bottom end 6b is configured to face the snow surface. In a preferred embodiment, the detonation chamber 6 is at a 15-degree angle relative to the tower 2 (see FIG. 3). The cover plate 8 preferably comprises opposing handles 10 for ease of handling.

(21) 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 FIG. 10), which is activated by a flow switch 23 (see FIG. 9). The cover 12 prevents ice and snow from accumulating on the spark plug 25. An electrical cable 13 connects the spark plug to a source of electricity (in this case, a battery 17 inside of the ignition box 16). In a preferred embodiment, the battery is a 12-volt, DC 1.2 Ah capacity sealed lead acid battery; however, the present invention is not limited to any particular type or size of battery as long as it is sufficient to supply the needed power to the spark plug.

(22) FIG. 3 is a side view of the present invention. As shown in this figure, the base 1 comprises a port 14 that is configured to receive the two gas supply lines 11, which run vertically up the length of the tower 2 (see FIG. 5). This figure also shows the shock-absorbing coils or isolator springs 15 that connect the two mounting brackets 7.

(23) FIG. 4 is a top view of the present invention. This figure shows where the section views of FIGS. 5 and 6 are taken. It also shows that the tower 2 is preferably cylindrical in shape with a constant outer diameter from top to bottom. The base 1 is preferably in the form of a square (when viewed from the top of the base), and the outer diameter of the tower is preferably less than the outer diameter of the base. The top end of the detonation chamber 6 is preferably rounded, as shown in this and the preceding figures, to prevent snow from accumulating on top of the detonation chamber. Both the detonation chamber 6 and the top end of the tower 2 preferably comprise lifting brackets 9 for ease of lifting and transportation (see also FIG. 7).

(24) FIG. 5 is a section view of the present invention taken at the line shown in FIG. 4, and FIG. 6 is a section view of the detonation chamber and the top part of the tower taken at the line shown in FIG. 4. As shown in these two figures, the gas supply lines 11 run from the base 1 to the top of the tower 2. See discussion of FIGS. 8 and 9, below, for further details. A spark plug 25 is situated inside of the detonation chamber 6 and configured to initiate combustion of the gases within the detonation chamber 6 when activated (see also FIG. 10).

(25) FIG. 7 is a perspective view of the detonation chamber and the top part of the tower. As shown in this figure, a first mounting bracket 7a is attached to the top part of the tower 2 and is comprised of two side members 7b and a front plate 7c. The two side members 7b are attached to either side of the top part of the tower 2, and the front plate 7c extends across the front of the top part of the tower and connects the two side members. A second mounting bracket 7d is attached to the detonation chamber and is comprised of two side members 7e and a front plate 7f. The two side members 7e are attached to either side of the detonation chamber, and the front plate 7f extends across the back of the detonation chamber and connects the two side members. Note that the first mounting bracket 7a is configured so that the front plate 7c is at the same angle as the detonation chamber 6 (as noted above, preferably a fifteen-degree angle). In this manner, there is a constant distance between the front plate 7c of the first mounting bracket 7a and the front plate 7f of the second mounting bracket 7d. The front plate 7c of the first mounting bracket 7a has the same width as the front plate 7f of the second mounting bracket 7d, which means that the outer diameter of the tower 2 is approximately the same as the outer diameter of the detonation chamber 6. A first pair of isolator springs 15 is oriented so that one isolator spring 15 is on top of the other. This pair of isolator springs is situated in between the front plates 7c, 7f of the mounting brackets 7a, 7d. Each isolator spring 15 is comprised of a helical cable isolator 15a that is inserted through a plurality of holes in two aluminum members 15b in a helical configuration. (That is, the cable isolator itself is comprised of helically wound wire rope, and the cable isolator is helically wound or inserted into the plurality of holes in the aluminum members.) The aluminum members 15b are used to maintain the cable isolator in a helically wound configuration and to secure the isolator springs 15 to the front plates 7c, 7f. One pair of isolator springs 15 is situated on a first side of the mounting brackets 7a, 7d, and an identical pair of isolator springs is situated on a second side of the mounting brackets. Note that the angle between the side members and the front plate on each of the mounting brackets 7a, 7e is preferably ninety degrees.

(26) 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.

(27) FIG. 8 is the same view as is shown in FIG. 7 but with the ladder, tower, cover plate, and one of the two mounting brackets removed. As noted above in connection with FIG. 2, the electrical cable 13 runs from the ignition box 16 to the spark plug 25. A signal wire 22 is connected to a flow switch 23, which is shown in FIG. 9. Each gas supply line 11 connects to the detonation chamber 6 at a pipe union 21. Inside of each pipe union 21 is a check valve (not shown). In a preferred embodiment, the check valve is a spring-loaded piston check valve manufactured by McMaster-Carr of Elmhurst, Illinois. The pipe unions 21 are preferably slanted downward to prevent any snow or sleet that might blow up into the detonation chamber from entering the gas supply lines. Note that the detonation chamber 6 preferably comprises a grip handle 24, which can be used by the operator to steady himself when standing on top of the tower 2. One could also attach a positioning lanyard (not shown) to the grip handle 24.

(28) FIG. 9 is a detail view of the ignition box of the present invention. In a preferred embodiment, the ignition box 16 is situated on the inside wall of the tower. The ignition box 16 contains a battery 17, two capacitors 18, a voltage converter 19, and two terminal blocks 20. Although two capacitors are shown here, the present invention would also work with a single capacitor. The voltage converter 19 converts 12-volt input (stored in the capacitor(s) from the battery) to 1.5 kilovolt output for the spark plug. The electrical cable 13 runs from the ignition box to the spark plug. A signal wire 22 runs from the ignition box to the flow switch 23. This figure shows the two gas lines 11, one of which preferably comprises a splice 26. The splice 26 is optional but facilitates seasonal testing of the gas lines. The other gas line 11 (that is, the one that does not have the splice) is connected to the flow switch 23. In a preferred embodiment, the gas line that is connected to the flow switch transports the fuel gas, which may be hydrogen or methane. The gas line that is not connected to the flow switch contains the oxidizer, which is typically oxygen. In this manner, the flow switch, which is configured to trigger the spark plug, is based on the flow of fuel gas only.

(29) In the particular configuration shown in FIG. 9, three wires extend out of the top of the right-hand terminal block 20. The first of these wires goes to the left-hand terminal block, which is connected to the capacitors 18; this wire is referred to as the common contact. The second wire goes to the voltage converter 19 (also referred to below as the spark generator), and the third wire goes to the battery 17. When gas flow begins, it triggers the flow switch 23 to connect the capacitor(s) 18 to the battery 17; therefore, while gas flow is occurring, the capacitor(s) is/are charging from the battery. When gas flow stops, the capacitor(s) is/are disconnected from the battery and connected to the voltage converter 19. The voltage converter drains the capacitor(s) completely and remains connected to the capacitor(s) until the flow switch 23 is reactivated. All switching is done within the brass body of the flow switch 23, which acts as a sensor to detect the flow of fuel gas. Gas flow is controlled remotely using control hardware that is kept at a gas storage facility separate and apart from the tower. The gas supply lines 11 run from the gas storage facility to the port 14 at the base of the tower.

(30) FIG. 10 is a detail view of the spark plug inside of the detonation chamber. In a preferred embodiment, the spark plug 25 is a custom-made spark plug comprised of a nylon threaded rod and stainless steel bolts. Because the explosions inside of the detonation chamber are so violent, ceramic spark plugs tend to shatter.

(31) FIG. 11 is a detail view of the isolator spring of the present invention. In a preferred embodiment, the isolator spring 15 is a modified version of the M Series Wire Rope Isolator manufactured by Isolation Dynamics Corporation of Farmingdale, New York. As shown in this figure, each isolator spring is comprised of two aluminum bars through which a single wire rope cable is helically threaded. As shown in FIG. 8, the present invention includes four isolator springs 15, each of which is attached to both mounting brackets 7a. 7d. In a preferred embodiment, each isolator spring 15 is configured to provide one inch of movement at a pull force of 4000 pounds on the bolts that secure the isolator spring to the mounting bracket.

C. Installation and Operation of the System

(32) 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.

(33) 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.

(34) 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 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.

(35) 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.

(36) 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.

(37) 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.

(38) 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.

(39) 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.

(40) 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.

D. Advantages of the Present Invention Over Prior Art

(41) 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.

(42) 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.

(43) 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.

(44) 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.