This application relates to flamethrowers and more particularly to a flamethrower with a plasma-generating spark ignition system.
Existing flamethrowers use torch ignition systems and are often composed of heavy metal parts making them cumbersome and costly. A typical torch ignition uses a pilot flame that often requires a secondary fuel source for the pilot flame. Then, the fuel from the primary fuel source is passed across the pilot flame. One risk with multiple fuel sources is that heat from either the pilot flame or from the full flame once ignited can cause one of the fuel sources to explode if there is not proper insulation between parts.
Existing flamethrowers are often composed of heavy, cumbersome metal parts because of the heat emitted from both the pilot flame and the ignited flame. What is needed is a cost-effective flamethrower with a lightweight construction and a safer and more efficient ignition system. The Spark Ignition Flamethrower provides a flamethrower that can be construct with composite plastics or polymers and a spark or plasma to ignite the flame.
In one embodiment, a composite flamethrower with a plasma ignition system includes a nozzle located on a first end of the composite flamethrower; a heat shield secured on the first end of the composite flamethrower around the nozzle; a fuel manifold coupled to the composite flamethrower configured to receive fuel from a fuel source; a fuel pump couple to the composite flamethrower configured to receive the fuel from the fuel manifold and conduct the fuel to the nozzle, which is configured to eject the fuel; a plasma-generating electrode configured to produce a plasma to ignite the fuel as the fuel exits the nozzle.
The composite flamethrower may further comprise a power coil and a control module; wherein the control module is configured to activate the fuel pump and the power coil thereby powering the plasma-generating electrodes to create the plasma. When fuel encounters the plasma the fuel ignites and a flame emits from the flamethrower.
In one embodiment, the composite flamethrower includes a nozzle insulator affixed to the first end of the composite flamethrower; and the plasma-generating electrode, the power coil, and the nozzle are mounted to the nozzle insulator.
In some embodiments, the composite flamethrower the plasma-generating electrode is nickel-chromium coated electrode or a copper electrode with a nickel-chromium coating.
In some embodiments, the nickel-chromium coated electrodes are mounted in a ceramic insulator.
In one embodiment, the composite flamethrower includes a top grip affixed to the composite flamethrower and a fuel tank removably connected to the fuel manifold. In this embodiment, the fuel tank is configured to supply fuel to the fuel manifold and to the fuel pump by force of gravity.
In one embodiment, the composite flamethrower includes a drop grip affixed to the composite flamethrower and a fuel tank removably attached to the fuel manifold. In this embodiment, a siphon tube is configured to draw the fuel into the fuel manifold.
In one embodiment, the composite flamethrower includes a hose adapter configured to connect the fuel manifold to the fuel source. The fuel source may be a detached fuel source such as a backpack tank.
In one exemplary embodiment, a composite flamethrower with a plasma ignition system includes a fuel manifold coupled to the composite flamethrower; a fuel pump; a fuel source; a grip having a trigger located on a first end of the composite flamethrower; a nozzle insulator located on a second end of the composite flamethrower; a nozzle coupled to the nozzle insulator; a spark electrode coupled to the nozzle insulator; a high voltage coil coupled to the nozzle insulator and configured to activate the spark electrode; and a control module configured to activate the fuel pump and the high voltage coil; wherein the fuel manifold is configured to supply fuel from the fuel source to the fuel pump and the fuel pump is configured to conduct the fuel to the nozzle which passes the fuel across the spark electrode thereby producing a flame.
In some embodiments, the composite flamethrower with a plasma ignition system includes a heat shield coupled to the second end of the composite flamethrower to protect internal components from excess heat. The heat shield may be comprised of a collar and a mica sheet wherein the mica sheet is located on the nozzle insulator and a tip of the nozzle and a tip of the spark electrode extend through the mica sheet.
In some embodiments, the spark electrode is comprised of two nickel-chromium coated electrodes mounted in the ceramic insulator.
In some embodiments, a distance between tips of the two nickel-chromium coated electrodes is between 2 mm to 10 mm.
In one exemplary embodiment, a composite flamethrower comprises a plasma-generating electrode configured to generate a plasma; and a nozzle configured to release fuel into the plasma generated by the plasma-generating electrode thereby producing a flame.
In one embodiment, a fuel manifold is coupled to the composite flamethrower; a fuel source is connected to the fuel manifold; and a fuel pump is within the composite flamethrower; wherein the fuel pump conducts the fuel from the fuel manifold to the nozzle.
In some embodiments, the composite flamethrower includes a high voltage coil that steps up a low voltage supplied by a battery to a high enough voltage to produce a plasma.
In some embodiments, a control module is in electric communication with the high voltage coil, the trigger, and the fuel pump. In response to the trigger, the control module may be configured to activate the fuel pump and the high-voltage coil which produces the plasma at the plasma-generating electrode.
In some embodiments, the electric potential across the plasma-generating electrodes is at least 375 kV.
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In some embodiments, the heat shield assembly 8 includes a collar 10 and a sheet 12. The heat shield assembly 8 may be comprised of a suitable heat and flame resistant material, such as metal or plastic. In one exemplary embodiment, the heat shield assembly 8 may be aluminum while the housing 2 is comprised of a polymer composite. The sheet 12 may be a mica sheet or any other suitable heat and flame resistant material. In some embodiments, the nozzle 4 and electrodes 6 may extend partially through the heat shield assembly 8. In such embodiments, only a small portion of the nozzle 4 and the electrodes 6 are exposed to the heat from the flame.
In some embodiments, the Spark Ignition Flamethrower 1 includes an attachment means 20 for attaching the Flamethrower 1 to another weapon, such as a rifle. In one embodiment, the attachment means 20 may be a Picatinny rail as is commonly used in military weaponry.
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In one embodiment, the electrode 6 is a spark electrode. Spark ignition uses a spark or arc between two electrodes. When the fuel encounters the spark, the fuel ignites to produce the flame.
In one embodiment, the electrode 6 is a plasma-generating electrode. The plasma-generating electrodes 6 impart significantly more energy in the creation of the arc between the electrodes. Generally, the ionization process of gas by high voltage takes several steps, as follows. First, the power coil 28 generates a high voltage across the electrodes 6 and there is an air gap between the electrodes. When the voltage first comes on, it “looks” for any randomly-occurring ionization event within the gap, as would happen if for example an ultraviolet photon happened to hit the surface of one of the electrodes at that time, or if that photon hit a gas molecule just right and temporarily dislodged one of its electrons within the air space in the gap. The voltage then accelerates the loose electron towards the (+) electrode and any positive ion towards the (−) electrode before they have the opportunity to recombine. They pick up energy from the field and speed up enough that if they happen to collide with another gas molecule on the way, it too gets ionized and the charged particles join in and get accelerated too. Soon you have an avalanche of ions approaching the electrodes and the air between them is rapidly becoming electrically conducting as it gets populated with ions. Then, when one of the positive ions smacks into the negative electrode, it busts loose a bunch of electrons which zoom off toward the positive electrode and very quickly the air gap's resistance falls to almost nothing and if there is no external resistance to limit the current, a huge current develops between the electrodes and since the current is huge and the air gap is still a (small) resistor, ohmic heating then raises the temperature of the ionized gas to incandescence and you have a power arc consisting of an extremely hot plasma.
The plasma improves the likelihood of ignition of the fuel over the spark because a plasma-generating electrode 6 produces a plasma or corona region that can ignite the fuel. In the spark ignition, the fuel must encounter the spark itself but in the plasma-generating embodiments, there is a plasma or corona region around the electrodes 6 which is a larger area capable of igniting the fuel.
In one embodiment, the power coil 28 is an induction coil and the electrode 6 is a plasma-generating electrode. The power coil 28 receives low voltage power from the battery 34 and steps up to a high voltage. The high voltage across the electrodes 6 generates a plasma by ionizing the gas in the atmosphere between the electrode tips. By way of example, a pulse frequency of at least 20 kHz may be used to produce the plasma. In one exemplary embodiment, the power coil 28 runs on 6 V input and outputs 375 kV with max output of 0.5 A.
In some exemplary embodiments, the tips of the spark electrodes 6 are placed between 10-15 mm from the tip of the nozzle 4. The distance between the tips of the spark electrodes 6 may be from 2-10 mm.
In one exemplary embodiment, the spark electrodes 6 are made of Nickel-Chromium Alloy. For example, an Ni80Cr20 alloy is 80% Nickel by weight and 20% Chromium by weight. Nickel-Chromium may be used over copper, aluminum, or steel because its resistance increases less when hot. Increased resistance causes more strain on upstream electrical components like the high power coil 28, and solid state switching.
Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.
It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings.
This application claims the benefit of U.S. Provisional Pat. App. No. 62/969,023 titled Spark Ignition System for a Flame Thrower, the disclosure of which is hereby incorporated by reference.
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