Low-energy flame thrower arrangement and a related method

Abstract

A method for creating flames, wherein combustible powder material is injected into a gas stream (120) and the dispersed mixture of powder and gas is ignited and discharged through a nozzle (124). An arrangement suitable for implementing the method is also disclosed.

Description

FIELD OF THE INVENTION[0001]The invention relates to a method and arrangement for producing special effects such as low-energy flames.BACKGROUND[0002]Pyrotechnic effects producing large flames have been traditionally created by quickly burning large amounts of flammable liquid or gas. For example, explosion-like special effects may be achieved by dispersing a container filled with a flammable liquid with a small explosive charge. As a result the liquid is dispersed and ignited in the surrounding air, thereby creating a large fireball. A large special effect may correspondingly require very large amounts, e.g. tens or hundreds of liters of flammable liquid.[0003]Continuous large flames are typically generated by burning large volumes of some suitable flammable gas, e.g. butane or propane streaming out of a nozzle. By varying the flow rate of the gas and the nozzle properties, flames of various sizes and shapes can be created.[0004]Burning large volumes of flammable high-energy fuels ...

AI Technical Summary

Benefits of technology

[0017]The gas stream may comprise a core and an envelope component. The gas flow in the core component may be faster than the flow speed of the envelope component. The gas flow in the core component may advantageously be at least slightly turbulent. Turbulence depends on the flow velocity. Especially when the flow velocity is low, a guiding structure may be applied to adjust the turbulence so as to maintain the flame stable and / or prevent it from going out. The gas flow in the envelope component may advantageously be laminar.

[0025]The nozzle may comprise a means for generating turbulence in the gas stream. The turbulence may be advantageously generated such that it occurs in the core component of the gas stream. Further advantageously, creation of turbulence is avoided in the envelope component of the gas stream.

[0036]As to the utility of the present invention, the inventors have surprisingly observed that the method and apparatus disclosed herein allow controlled, relatively slow burning of powdered material that according to prior art would either burn explosively or not ignite at all. Inventors believe that the flow of gas as disclosed in various embodiments of the invention contribute significantly to the phenomenon. The invention solves shortcomings of the prior art for example by creating flames that emit relatively low amount of heat since they burn at an unusually slow rate for the material. The invention may be applied to produce relatively large flames that can be safely used even by inexperienced operators and indoors. As a further benefit, fuel, which is not classified as hazardous material, may be used.

Problems solved by technology

As a result the liquid is dispersed and ignited in the surrounding air, thereby creating a large fireball.

Burning large volumes of flammable high-energy fuels such as gasoline or propane causes significant safety risks as lots of heat is released in the combustion process.

This significantly limits the usability of such methods.

For example, creating large flames indoors is very challenging and in many cases impossible because of the safety risks.

These solutions are not completely risk-free as the smoke may be toxic and / or the compounds may explode in an uncontrollable manner.

In addition, they require licenses and clearances to be used legally and are hazardous in storage and transport.

The resulting mixtures may develop toxic gases.

Chlorinated materials may generate e.g. phosgene which is toxic even in small amounts.

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