Delay igniter caps, blowback igniter caps, and combination igniter caps for thermal lances, and thermal lances including such igniter caps

Abstract

An igniter cap for a thermal lance, comprising a proximal end adapted to receive the thermal lance, a distal end, a housing having side walls extending from the proximal end to the distal end and defining a passageway, and primary and secondary fuels disposed within the passageway. At least a portion of the primary fuel contacts the secondary fuel and / or the distal end is substantially sealed and the proximal end includes at least one opening such that when the thermal lance is received at the proximal end of the igniter cap, gas flows axially through the primary and secondary fuels and is then redirected by the sealed distal end to flow back through the primary and secondary fuels and out through the at least one opening along the outer surface of the thermal lance. The thermal lance also includes such an igniter cap.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the priority of U.S. Provisional Patent Application No. 63 / 335,418, filed on April 27, 2022, the disclosure of which is incorporated herein by reference in its entirety. (Technical Field)

[0002] The present invention is directed to an igniter cap for igniting a thermal lance and a lance including such an igniter cap, and more specifically, an igniter cap that includes features for directing thermal energy from the igniter cap along an outer surface of the thermal lance, an igniter cap that provides delayed ignition of the thermal lance, an igniter cap that performs both functions, and a thermal lance including such an igniter cap.

Background Art

[0003] In the metal industry, containers such as furnaces, ladles, tundishes, and rail cars are used to melt, hold, and transport molten iron and non - ferrous metals. These containers have discharge ports of various shapes and orientations that are used to discharge molten metal from the inside of the container. During normal operation, these discharge ports can become clogged or blocked. The industry standard is to use a thermal lance to burn through obstructions and remove clogging of the discharge ports. U.S. Patent Nos. 4,450,986 (Patent Document 1), 4,746,037, 4,877,161, 7,537,723, 7,563,407, and 11,187,461, and U.S. Patent Application Publication No. 2020 / 0318208 are directed to such thermal lances and methods for removing clogging of such discharge ports using them.

[0004] The use of thermal lances, with or without an auxiliary igniter, is a standard practice in the metal industry, but there are many problems regarding the reliability of thermal lance ignition.

[0005] The thermal lance is mainly made of low-carbon steel and sometimes contains magnesium or tungsten rods. These solid metal components require a significant amount of energy input for combustion to occur. It is difficult to increase the thermal energy from ambient conditions to the level required for combustion.

[0006] For the effective and reliable ignition and combustion of the thermal lance, there are several factors that must be considered, including the significant amount of energy required for ignition, the sensitivity of the ignition process to the oxygen flow, and the provision of sufficient energy after ignition. Furthermore, the process is not easily automated and generally requires a human operator to physically ignite the thermal lance or the provision of an auxiliary igniter not integrated into the lance. This lack of automation raises concerns about the safety and ergonomics of the process for the operator.

[0007] The standard practice for ignition (initiation of combustion) is to immerse the end of the thermal lance into the molten metal while applying a low flow of oxygen. The oxygen flow is often controlled by an imprecise trigger valve, and a trained operator is required to provide the correct flow of oxygen throughout the process. This ignition method is physically dangerous and difficult to control.

[0008] To increase the reliability of hot lance combustion, one or more additional fuel ignition / combustion chains are often used. The fuel can be provided within an auxiliary igniter, which can include two stages of fuel. The primary fuel is a material that is most easily ignited and has a very low autoignition temperature, such that relatively little thermal energy is required for this material to begin burning and initiate the ignition / combustion chain. However, the combustion of this material occurs rapidly and only lasts for a short period, generating insufficient energy to ignite the solid metal components of the hot lance. A secondary fuel with intermediate ignition energy requirements is needed to fill that gap. The primary fuel generates sufficient thermal energy to initiate the combustion of the secondary fuel. The secondary fuel burns over a longer period and provides a more exothermic combustion reaction, thereby generating more thermal energy than the primary fuel. In theory, the secondary fuel generates sufficient thermal energy to initiate the combustion of the solid metal components of the hot lance.

[0009] If the primary stage fuel is a pyrotechnic fuse, exposure of the fuse to a high-temperature environment is required for ignition. In the molten metal industry, there is not always a sufficient temperature to perform this task.

[0010] If the primary stage fuel is a powdered material with low ignition energy requirements, such as very fine powdered zirconium, a high flow of 100% pure oxygen is required for ignition. More specifically, precise concentrations of the powder and 100% oxygen within an internal chamber are required for spontaneous combustion of the powder. This concentration is extremely difficult to reliably achieve within the metal industry.

[0011] If the primary stage fuel is a primer similar to those used in ammunition, movement of a secondary component is required to strike the primer in the exact correct location. Controlling the speed, direction, and position of this striking component is difficult to reliably achieve within the metal industry.

[0012] In all three of these ignition methods, the primary fuel must be capable of igniting properly, generating sufficient energy, and transferring this energy to the secondary fuel to continue the ignition / combustion chain.

[0013] Accordingly, there are several problems associated with prior art thermal lances with or without an auxiliary igniter. These problems include reliable ignition of the ignition / combustion chain, premature ignition, insufficient time during ignition to allow the operator to initiate the flow of oxygen and position the thermal lance within the discharge port, and reliable ignition of the thermal lance itself. The present invention addresses all of these problems.

Prior Art Documents

Patent Documents

[0014]

Patent Document 1

Summary of the Invention

Means for Solving the Problems

[0015] The present invention is directed to a blowback igniter cap for a thermal lance comprising a proximal end adapted to receive the thermal lance, a distal end, a housing having a sidewall extending from the proximal end to the distal end and defining a passageway, and an internal primary fuel and a secondary fuel disposed within the passageway of the housing. The distal end of the blowback igniter cap is substantially sealed and the proximal end of the blowback igniter cap includes at least one opening such that when the thermal lance is received at the proximal end of the blowback igniter cap, gas flows axially from the thermal lance, into the proximal end of the blowback igniter cap, through the internal primary fuel and the secondary fuel, then is redirected by the sealed distal end of the housing to flow back through the internal primary fuel and the secondary fuel and out through the at least one opening along the outer surface of the thermal lance.

[0016] The plug may cover the distal end of the blowback igniter cap, thereby substantially sealing the distal end of the blowback igniter cap.

[0017] The blowback igniter cap may further comprise or define an attachment ring that includes or defines at least one opening. The attachment ring may have a central opening for receiving the thermal lance. The at least one opening may be a hole or opening passing through the attachment ring, or the attachment ring may be divided into portions and the at least one opening may be provided between the portions. The attachment ring may be fixedly attached to the thermal lance.

[0018] The blowback igniter cap may further comprise a porous barrier that fills an opening at the distal end through which the fuse passes and / or a portion of the passage of the housing and serves as a partition between the primary fuel and / or secondary fuel and the distal end of the thermal lance when the thermal lance is received within the blowback igniter cap.

[0019] The present invention also relates to a delay igniter cap for a thermal lance comprising a proximal end adapted to receive the thermal lance, a distal end, a housing having side walls extending from the proximal end to the distal end and defining a passage, and internal primary fuel and secondary fuel disposed within the passage of the housing. The internal primary fuel surrounds the secondary fuel.

[0020] The internal primary fuel and / or secondary fuel may be porous or may include openings to allow gas to flow from the proximal end of the delay igniter cap to the distal end of the delay igniter cap when the delay igniter cap is attached to the thermal lance. The secondary fuel may be a central core within the passage of the housing, and the internal primary fuel may be positioned between the side wall of the housing and the secondary fuel and may be provided in the form of a spiral or coil surrounding the secondary fuel.

[0021] The internal primary fuel may comprise a protected portion separated from the secondary fuel by a sheath that prevents and / or reduces cross-ignition between the internal primary fuel and the secondary fuel, and an unprotected portion that is in direct contact with the secondary fuel. The protected portion of the internal primary fuel may have a higher fuel volume than the unprotected portion of the internal primary fuel.

[0022] A porous barrier may be provided that fills part of the passage of the housing and serves as a partition between the primary fuel and / or secondary fuel and the distal end of the thermal lance when the thermal lance is received within the igniter cap.

[0023] The delayed igniter cap may further comprise a recess at the proximal end of the housing for receiving the thermal lance such that the distal end of the thermal lance is adjacent to and / or in contact with the internal primary fuel and / or secondary fuel, and a fuse extending out of the distal end of the delayed igniter cap from the internal primary fuel.

[0024] The delayed igniter cap may further comprise an external primary fuel provided on the exterior of the housing between the fuse and the internal primary fuel. The external primary fuel may be provided as a coil or spiral and may be surrounded by a sheath that prevents combustion of one portion of the external primary fuel from igniting another portion of the external primary fuel and / or igniting the housing.

[0025] The present invention also relates to a combined igniter cap for a thermal lance comprising a proximal end adapted to receive the thermal lance, a distal end, a housing having a side wall extending from the proximal end to the distal end and defining a passageway, and an internal primary fuel and a secondary fuel disposed within the passageway of the housing. The distal end of the combined igniter cap is substantially sealed and the proximal end of the combined igniter cap includes at least one opening such that when the thermal lance is received at the proximal end of the combined igniter cap, gas flows axially from the thermal lance, through the internal primary fuel and the secondary fuel, into the proximal end of the combined igniter cap and then is redirected through the internal primary fuel and the secondary fuel by the sealed distal end of the housing and exits out along the outer surface of the thermal lance through the at least one opening. The internal primary fuel surrounds the secondary fuel.

[0026] The internal primary fuel and / or the secondary fuel may be porous or may include openings to enable gas to flow from the proximal end of the combined igniter cap to the distal end of the combined igniter cap when the combined igniter cap is attached to the thermal lance. The secondary fuel may be a central core within the passageway of the housing and the internal primary fuel may be positioned between the side wall of the housing and the secondary fuel and may be provided in the form of a spiral or coil surrounding the secondary fuel.

[0027] The internal primary fuel may comprise a protected portion separated from the secondary fuel by a sheath that prevents and / or reduces cross-ignition between the internal primary fuel and the secondary fuel and an unprotected portion that is in direct contact with the secondary fuel. The protected portion of the internal primary fuel may have a higher fuel volume than the unprotected portion of the internal primary fuel.

[0028] The combined igniter cap may further comprise an external primary fuel provided on the outside of the housing between the fuse and the internal primary fuel. The external primary fuel may be provided as a coil or spiral and may be surrounded by a sheath that prevents combustion of one portion of the external primary fuel from igniting another portion of the external primary fuel and / or igniting the housing.

[0029] The plug may cover the distal end of the combination igniter cap, thereby substantially sealing the distal end of the combination igniter cap.

[0030] The combination igniter cap may further comprise an attachment ring that includes or defines at least one opening. The attachment ring may have a central opening for receiving the thermal lance. The at least one opening may be a hole or opening passing through the attachment ring, or the attachment ring may be divided into portions and the at least one opening may be provided between the portions. The attachment ring may be fixedly attached to the thermal lance.

[0031] The combination igniter cap may further comprise a porous barrier that fills an opening at the distal end through which the fuse passes and / or a portion of the passage of the housing and that functions as a partition between the primary fuel and / or secondary fuel and the distal end of the thermal lance when the thermal lance is received within the combination igniter cap.

[0032] The present invention also relates to a thermal lance system comprising a delay igniter cap, a blowback igniter cap, or a combination igniter cap and a thermal lance. The distal end of the thermal lance is received at the proximal end of the igniter cap.

[0033] When a blowback igniter cap or a combination igniter cap is provided, tertiary fuel may be provided within the thermal lance adjacent to the secondary fuel of the igniter cap. The tertiary fuel may have a higher energy density than the secondary fuel and / or a lower initial energy requirement for combustion than components of the thermal lance.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0050] As used herein, the terms "comprising" and "including" are non-limiting and have the same meaning and may be synonymous with "including" or "characterized by". Any numerical value is represented using a period as a decimal point and a comma as a digit separator; for example, 1,234 would be 1,234 (one thousand two hundred thirty four) and 1.2 would be 1.2 (one and two tenths). Unless otherwise explicitly defined, all numbers, such as those representing values, ranges, amounts, or percentages, may be read as if the word "about" preceded them, even if the term does not explicitly appear. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, the range "1 to 10" includes every sub-range (and including those) between the recited minimum value of 1 and the recited maximum value of 10, i.e., every sub-range that begins with a minimum value equal to or greater than 1 and ends with a maximum value equal to or less than 10, and all sub-ranges therebetween, such as 1 to 6.3, or 5.5 to 10, or 2.7 to 6.1. The plural form encompasses the singular form and vice versa. When ranges are given, any endpoints of those ranges and / or numbers within those ranges may be combined with the scope of the present invention. The terms "including", "such as", "for example", and the like mean "including, but not limited to / such as / ".

[0051] For the purposes of the following description, spatial orientation terms as used are to be associated with the embodiments being referred to as so oriented in the accompanying drawings, figures, or otherwise described in detail hereinafter. However, it is to be understood that the embodiments described hereinafter may take many alternative variations and configurations. It is also to be understood that the specific components, devices, features, and sequences of operations illustrated in the accompanying drawings, figures, or otherwise described herein are merely exemplary and should not be regarded as limiting.

[0052] The present invention is directed to a blowback igniter cap 100 (Figs. 1 and 2) for a thermal lance 1, a thermal lance system (Figs. 1 and 2) including the blowback igniter cap 100, a delay igniter cap 10 (Fig. 5) for a thermal lance 1, a thermal lance system (Fig. 5) including the delay igniter cap 10, a combined igniter cap 200 (Figs. 15 and 16) having both the characteristics of the delay igniter cap 10 and the blowback igniter cap 100, and a thermal lance system (Figs. 15 and 16) including the combined igniter cap 200. The thermal lance can be used to melt metal, more specifically, to melt metal to open a taphole in a steelmaking or other metal production vessel.

[0053] As shown in Figs. 1, 2, 5, 15, and 16, the thermal lance 1 includes an outer housing 16 having a sidewall 18 extending from a proximal end 12 of the thermal lance 1 to a distal end 14 of the thermal lance 1 and defining a passage 20, and an inner housing 22 having a sidewall 24 defining a passage 26, the inner housing 22 being contained within the outer housing 16. A central core 28 having one or more passages is contained within the passage 26 of the inner housing 22. The inner housing 22 may have a length shorter than the length of the outer housing 16, whereby the distal end 30 of the inner housing 22 is located within the passage 20 of the outer housing 16 and is proximally spaced from the distal end 32 of the outer housing 16. The central core 28 may extend into the passage 20 of the outer housing 16 beyond the distal end 30 of the inner housing 22.

[0054] The outer housing 16 and the inner housing 22 may be substantially cylindrical tubes, and the sidewall 18 of the inner housing 22 may be concentric with the sidewall 18 of the outer housing 16. The central core 28 may have a substantially cylindrical outer surface and may fill the passage 26 of the inner housing 22. In one embodiment, the central core 28 has a helical shape with layers of material wound around a central axis. The helical shape defines several concentric passages through the central core 28.

[0055] The outer housing 16, the inner housing 22, and the central core 28 can be made of any suitable metal or metal sheet including, but not limited to, stainless steel, low carbon steel, high carbon steel, alloy steel, magnesium, tungsten, and combinations thereof.

[0056] The proximal end 12 of the thermal lance 1 has a fitting to which a gas source is attached, whereby gas flows from the proximal end 12 of the thermal lance 1, through the central core 28, and out from the distal end 14 of the thermal lance 1. Further, the gas can flow through any space provided between the outer housing 16 and the inner housing 22 and / or between the inner housing 22 and the central core 28. The gas can be any gas containing oxygen that is suitable for promoting combustion. The gas will be referred to herein as oxygen.

[0057] The distal end 14 of the thermal lance 1 can include a cap 34 for concentrating the flow of oxygen. The cap 34 can have a substantially conical shape that narrows the passage 20 of the outer housing 16 and reduces the size of the distal end 14 of the thermal lance 1.

[0058] The thermal lance 1 can further be telescopic to increase its length as described in U.S. Pat. Nos. 4,450,986, 4,746,037, and 4,877,161, which are hereby incorporated herein by reference in their entireties.

[0059] In use, the distal end 14 of the thermal lance 1 is ignited and the components of the thermal lance 1 are consumed by the heat of ignition and the combustion reaction from the oxygen flowing through the thermal lance 1.

[0060] The blowback igniter cap 100 of the present invention is attached to the distal end 14 of the thermal lance 1.

[0061] As shown in FIGS. 1 and 2, the blowback igniter cap 100 includes a housing 140 having a proximal end 136, a distal end 138, and a sidewall 142 extending from the proximal end 136 to the distal end 138 and defining a passageway 144, and an internal primary fuel 146 and a secondary fuel 148 disposed within the passageway 144 of the housing 140. The internal primary fuel 146 and the secondary fuel 148 can be any suitable combustible material capable of ignition in the presence of oxygen, including but not limited to: pyrotechnic fuses; artillery fuses; metal powders of aluminum, iron, titanium, magnesium, tungsten, and / or steel; non-metal powders of wood, plastic, and / or synthetic materials; metal chips or flakes of aluminum, iron, titanium, magnesium, tungsten, and / or steel; steel wool; synthetic or organic foams; synthetic or organic textiles; and chemical mixtures of high-energy oxidizers and fuels. The internal primary fuel 146 and / or the secondary fuel 148 is porous so that when the blowback igniter cap 100 is attached to the thermal lance 1, oxygen from the thermal lance 1 can flow from the proximal end 136 of the blowback igniter cap 100 to the distal end 138 of the blowback igniter cap 100.

[0062] The internal primary fuel 146 and the secondary fuel 148 can be positioned relative to each other within the passageway in any suitable arrangement in which at least a portion of the internal primary fuel 146 contacts the secondary fuel 148. For example, in one embodiment, as shown in FIGS. 1 and 2, the secondary fuel 148 surrounds the internal primary fuel 146.

[0063] The distal end 166 of the housing 140 can be substantially sealed and include an opening 168 that allows the fuse 154 to pass through. The distal end 166 of the housing 140 can be sealed in any suitable manner that substantially prevents oxygen flowing from the proximal end 136 of the blowback igniter cap 100 to the distal end 138 of the blowback igniter cap 100 from flowing out of the distal end 138 of the blowback igniter cap 100.

[0064] A plug or cap 170 can cover the distal end 166 of the housing 140 of the blowback igniter cap 100 such that the distal end 166 of the housing 140 is sealed. The plug 170 can be made of any suitable combustible material that can be firmly fixed to the distal end 166 of the housing 140. Such materials include, but are not limited to, steel, stainless steel, iron, wood, cardboard, rubber, cork, plastic, tape, and other metallic, synthetic, or organic materials.

[0065] Alternatively, the distal end 166 of the housing 140 of the blowback igniter cap 100 can be sealed by forming, crimping, welding, riveting, driving, or bending.

[0066] A recess 158 for receiving the thermal lance 1 is provided within the proximal end 160 of the housing 140 of the blowback igniter cap 100. An attachment ring 172 having a central opening 174 for receiving the thermal lance 1 is provided within the recess 158 of the housing 140. The attachment ring 172 includes at least one opening 176 that allows oxygen to flow between the thermal lance 1 and the housing 140 of the blowback igniter cap 100 through the attachment ring 172.

[0067] At least one opening 176 within the attachment ring 172 can be provided as a hole or opening passing through the attachment ring 172, or the attachment ring 172 can be divided into parts and the opening 176 can be provided between the parts. When a plurality of openings 176 are provided, the openings 176 can be equally spaced around the attachment ring 172, for example, at 180° (two openings), 120° (three openings), 90° (four openings), or 45° (eight openings), or can be provided at different distances from each other.

[0068] In the blowback igniter cap 100, as shown in FIGS. 1 and 2, oxygen flows axially from the hot lance 1 through the internal primary fuel 146 and the secondary fuel 148 into the proximal end 136 of the blowback igniter cap 100, and then is redirected axially back by the sealed distal end 166 of the housing 140, passes through the internal primary fuel 146 and the secondary fuel 148, and exits through the opening 176 in the mounting ring 172.

[0069] The total surface area of the openings 176 in the mounting ring 172 is greater than any gap between the fuse 154 and the opening 168 in the distal end 166 of the housing 140 such that most of the oxygen exits along the outer surface of the outer housing 16 of the hot lance 1 through the proximal end 136 of the blowback igniter cap 100.

[0070] The mounting ring 172 can be made of any suitable material that allows for secure attachment of the mounting ring 172 to the housing 140 of the blowback igniter cap 100 and the outer housing 16 of the hot lance 1. Such materials include metals, organics, plastics, ceramics, and rubbers. The attachment of the mounting ring 172 to the housing 140 of the blowback igniter cap 100 and the outer housing 16 of the hot lance 1 can be accomplished by any suitable method that ensures that the blowback igniter cap 100 will not be removed from or move relative to the hot lance 1 by the gas pressure of oxygen strongly affecting the sealed distal end 166 of the housing 140 of the blowback igniter cap 100 or by the blowback igniter cap 100 strongly affecting a solid object. Such methods include, but are not limited to, welding, crimping, compression, pinning, riveting, rubber inserts, metal inserts, springs, clips, pins, interlocking geometries, and corresponding screw connections.

[0071] The fuse 154 extends out from the internal primary fuel 146 to the distal end 166 of the blowback igniter cap 100. The fuse 154 can be manually ignited using a torch lamp, igniter, or high-temperature element, or any other suitable ignition source, or can be self-ignited when the temperature or surface exceeds the self-ignition temperature of the fuse 154 to initiate the combustion of the internal primary fuel. The combustion of the internal primary fuel 146 proceeds along a path through the internal primary fuel 146 and ignites the secondary fuel 148.

[0072] Optionally, a porous barrier 178 can be provided to separate the secondary fuel 148 from the thermal lance 1. The barrier can be made of any suitable material that fits snugly within the housing 140 of the blowback igniter cap 100, is porous to allow the flow of oxygen through it, and has a porosity that is fine enough to contain the secondary fuel 148. Such materials include, but are not limited to, cloth, metal, synthetic resin, or foam.

[0073] Optionally, a tertiary fuel 180 can be provided between the central core 28 and the outer housing 16 of the thermal lance 1, where the tertiary fuel 180 is mixed with the components of the thermal lance 1. The tertiary fuel 180 can have a higher energy density than the secondary fuel 148 and / or a lower initial energy requirement for combustion than the components of the thermal lance 1. The tertiary fuel 180 can be, for example, compressed metal flakes, powder, or shavings, steel wool, wood, plastic, or non-metallic powder of synthetic material, high-density synthetic or organic foam, or high-density synthetic or organic fabric. The tertiary fuel 180 is ignited by the combustion of the secondary fuel 148 and aids in the ignition of the components of the thermal lance 1.

[0074] The blowback igniter cap 100 of the present invention provides several advantages over prior art igniter caps.

[0075] As discussed above, when the distal end of the igniter cap is not sealed, oxygen flows axially in one direction along the length of the igniter cap and exits outside the distal end of the igniter cap. In this case, the oxygen mainly interacts with the inner surface of the housing of the thermal lance 1. In this contact, although there is often sufficient fuel and oxygen for combustion of the thermal lance 1, it is difficult to ensure sufficient thermal energy is provided to all components of the thermal lance 1 for combustion to start. This is exacerbated when high oxygen pressure and flow are used, and thus the combustion reaction requires low-pressure oxygen to react reliably.

[0076] The dependence on low-pressure / low-flow oxygen can be reduced when the surface area of the thermal lance 1 exposed to oxygen and thermal energy is increased. As shown in FIGS. 1 and 2, by using a blowback igniter cap 100 having a sealed distal end 166, the oxygen exiting the thermal lance 1 interacts with the internal primary fuel 146 and secondary fuel 148 and is then reversed in direction and exits from the blowback igniter cap 100 along the outer surface of the thermal lance 1. This exposes the outer surface of the thermal lance 1 to the oxygen flow and enhances the combustion of the thermal lance 1. This flow path is highlighted in FIGS. 3 and 4 which show the difference in the spark profile exiting the housing of the igniter cap. As can be seen in FIG. 3, for an igniter cap 82 with an open distal end, the spark is directed outward from the distal end of the igniter cap 82, while for the blowback igniter cap 100 with the distal end 166 sealed as shown in FIG. 4, the spark is directed outward from the proximal end 136 of the blowback igniter cap 100 along the outer surface of the thermal lance 1.

[0077] Furthermore, by using the oxygen flow within the blowback igniter cap 100, the thermal energy generated from the combustion of the internal primary fuel 146 and secondary fuel 148 follows the flow path of the oxygen and is directed towards the thermal lance 1 instead of away from it. This increases the heat transfer rate between the fuels 146, 148 and the components of the thermal lance 1. This preheating effect enhances the reliability of a complete ignition of the thermal lance 1.

[0078] In addition, instead of being separate components, the direct integration of the blowback igniter cap 100 to the thermal lance 1 enhances the ease of operation and the reliability of a complete ignition of the thermal lance 1. Inventory management is rationalized, the number of components is reduced from two to one, and the likelihood that the thermal lance 1 will be used correctly is increased.

[0079] Conventional igniter caps are optimized for the ignition of primary fuel and are not designed to enhance heat transfer to the thermal lance 1 itself. The thermal lance system of the present invention with the blowback igniter cap 100 of the present invention combines the igniter and the thermal lance 1 into one device that has adapted heat transfer throughout all stages of fuel ignition and optimizes combustion along all steps.

[0080] Furthermore, directly integrating the blowback igniter cap 100 of the present invention to the thermal lance 1 enables the use of a tertiary fuel 180. The secondary fuel 148 only needs to generate enough thermal energy to ignite the tertiary fuel 180. Once ignited, the tertiary fuel 180 generates thermal energy as close as possible to the components of the thermal lance 1. This maximizes the efficiency of heat transfer to the components of the thermal lance 1. Conventional igniter caps and thermal lances rely only on the thermal energy from primary and secondary fuels that are physically separated from the components of the thermal lance.

[0081] The delay igniter cap 10 of the present invention is attached to the distal end 14 of the thermal lance 1.

[0082] As shown in FIG. 5, the delay igniter cap 10 includes a proximal end 36, a distal end 38, a housing 40 having a side wall 42 that extends from the proximal end 36 to the distal end 38 and defines a passage 44, and an internal primary fuel 46 and a secondary fuel 48 disposed within the passage 44 of the housing 40.

[0083] The internal primary fuel 46 and the secondary fuel 48 can be any suitable combustible material that is ignitable in the presence of oxygen and includes, but is not limited to, pyrotechnic fuses, artillery fuses, metal powders of aluminum, iron, titanium, magnesium, tungsten, and / or steel, non-metal powders of wood, plastic, and / or synthetic materials, metal chips or flakes of aluminum, iron, titanium, magnesium, tungsten, and / or steel, steel wool, synthetic or organic foams, synthetic or organic fabrics, and chemical mixtures composed of high-energy oxidizers and fuels. The internal primary fuel 46 and / or the secondary fuel 48 is porous or includes openings to allow oxygen to flow from the proximal end 36 of the delay igniter cap 10 to the distal end 38 of the delay igniter cap 10 when the delay igniter cap 10 is attached to the thermal lance 1.

[0084] Within the housing 40, the internal primary fuel 46 surrounds the secondary fuel 48. As shown in FIG. 5, the secondary fuel 48 can be a central core within the passage 44 of the housing 40, and the internal primary fuel 46 can be positioned between the side wall 42 of the housing 40 and the secondary fuel 48 and provided in the form of a spiral or coil that surrounds the secondary fuel 48. The turns of the spiral can be wound such that the turns are spaced apart or such that the turns of the spiral contact each other. By way of example, as shown in FIG. 5, the turns of the spiral within the protected portion 50 of the internal primary fuel 46 can be spaced apart from each other, while the turns of the non-protected portion 52 of the internal primary fuel 46 can contact each other.

[0085] The secondary fuel 48 may comprise two or more parts. For example, as shown in FIG. 5, the secondary fuel 48 may comprise two or more substantially cylindrical parts 48a, 48b extending longitudinally in the passage 44 of the housing 40. Alternatively, the internal primary fuel 46 may completely fill the space between the side wall 42 of the housing 40 and the secondary fuel 48, and / or the secondary fuel 48 may be a material that completely fills the space within the housing 40 defined by the internal primary fuel 46.

[0086] The fuse 54 extends outside the distal end 38 of the delay igniter cap 10 from the internal primary fuel 46. The fuse 54 can be manually ignited using a torch lamp, igniter, high temperature element, or any other suitable ignition source, or can auto-ignite when exposed to a temperature or surface above the auto-ignition temperature of the fuse 54 to initiate combustion of the internal primary fuel. The combustion of the internal primary fuel 46 proceeds along a path through the internal primary fuel 46, and when the burning internal primary fuel 46 contacts the secondary fuel 48, the secondary fuel 48 is ignited and begins to burn.

[0087] The protected portion 50 of the internal primary fuel 46 may be separated from the secondary fuel 48 by a sheath, which prevents and / or reduces cross-ignition of the internal primary fuel 46 with the secondary fuel 48 while still allowing the secondary fuel 48 to be heated by the combustion of the protected portion 50 of the internal primary fuel 46. The unprotected portion 52 of the internal primary fuel 46 is in direct contact with the secondary fuel 48, whereby ignition and combustion of the unprotected portion 52 of the internal primary fuel 46 ignite the secondary fuel 48. The protected portion 50 of the internal primary fuel 46 may also prevent the entire internal primary fuel 46 from igniting simultaneously. For example, when the internal primary fuel 46 is a spiral, as shown in FIG. 5, the sheath surrounding the protected portion 50 of the internal primary fuel 46 suppresses the ignition and combustion of the internal primary fuel 46, whereby the ignition and combustion of the internal primary fuel 46 follow the spiral path and do not jump from one rotation of the spiral to an adjacent rotation of the spiral. When the combustion of the internal primary fuel 46 reaches the unprotected portion 52 of the internal primary fuel 46, all cross-ignitions of the rotations of the spiral in the unprotected portion 52 can occur simultaneously and ignite the secondary fuel 48.

[0088] The protected portion 50 of the internal primary fuel 46 can have a higher fuel volume than the unprotected portion 52 of the internal primary fuel 46. For example, when the internal primary fuel 46 is a spiral or coil, as shown in FIG. 5, the protected portion 50 of the internal primary fuel 46 includes more turns of the spiral than the unprotected portion 52 of the internal primary fuel 46.

[0089] In the embodiment shown in FIG. 5, the housing 40 can be a phenolic resin tube, the internal primary fuel 46 can be a fuse, and the secondary fuel 48 can be steel wool.

[0090] The side wall 42 of the housing 40 can include ventilation holes 56 and can have a substantially cylindrical shape.

[0091] The housing 40 can be made of any suitable combustible material that includes the internal primary fuel 46 and the secondary fuel 48 and has structural integrity for attaching the delay igniter cap 10 to the thermal lance 1. Such materials include, but are not limited to, phenolic resin, cardboard, plastic, low-carbon steel, high-carbon steel, stainless steel, and fiberglass.

[0092] A recess 58 can be provided within the proximal end 60 of the housing 40 of the delay igniter cap 10. In use, the thermal lance 1 is inserted into the recess 58 of the housing 40 of the delay igniter cap 10 until or when the distal end 14 of the thermal lance 1 is adjacent to and / or in contact with the internal primary fuel 46 and / or the secondary fuel 48. The inner dimensions of the recess 58 correspond to the outer dimensions of the housing 40 of the delay igniter cap 10 and can provide a friction fit between the delay igniter cap 10 and the thermal lance 1. Alternatively, the delay igniter cap 10 can be attached to the thermal lance 1 using any suitable method including, but not limited to, welding, riveting, adhesion, compression forming such as crimping or compression, friction fit, rubber inserts, metal inserts, springs, clips, pins, mating geometries, and corresponding screw connections.

[0093] As shown in FIG. 5, the plug 62 of the secondary fuel 48 fills the passage 44 of the housing 40 and can serve as a partition between the fuels 46, 48 of the delay igniter cap 10 and the distal end 14 of the hot lance 1.

[0094] Optionally, an external primary fuel 64 can be provided between the fuse 54 and the internal primary fuel 46. The external primary fuel 64 can be continuous with and the same as the internal primary fuel 46 or can be different from the internal primary fuel 46. The external primary fuel 64 can be attached to the outer surface of the housing 40 of the delay igniter cap 10. As shown in FIG. 5, the external primary fuel 64 can be provided as a coil or spiral. The external primary fuel 64 can be surrounded by a sheath that prevents combustion of one portion of the external primary fuel 64 from igniting another portion of the external primary fuel 64 and / or the housing 40. For example, the sheath can prevent one rotation of the coil from igniting another rotation of the coil and / or the housing 40. Thus, when the fuse 54 ignites the external primary fuel 64, combustion proceeds along the coil of the external primary fuel 64 to the spiral of the internal primary fuel 46 contained within the housing 40 and then onto the secondary fuel 48 as described above.

[0095] In the delay igniter cap 10, oxygen flows axially from the hot lance 1 into the proximal end 36 of the delay igniter cap 10 through the internal primary fuel 46 and the secondary fuel 48 and out through the open distal end 38 of the delay igniter cap 10.

[0096] The delay igniter cap 10 of the present invention provides many advantages over prior art ignition systems.

[0097] Regarding self-igniting systems, ignition may not occur if the temperature of the environment or object to which the fuse is exposed is not sufficient for self-ignition (usually above 600°F), or ignition may be too early if the fuse touches a hot surface, is exposed to a flame, or is exposed to ambient temperatures above the self-ignition temperature. Further, when the fuse is ignited, the operator has only 10 - 15 seconds to move the heat lance to the correct position and turn on the oxygen. If the fuse is completely consumed before oxygen is applied, the lance will not ignite.

[0098] Regarding the delay igniter cap 10 of the present invention, the provision of the external primary fuel 64 and the sheath covering of the protective portion 50 of the internal primary fuel 46 enable increased control of the overall burn time of the primary fuels 46, 64. The external primary fuel 64 can burn for up to 60 seconds, and the positioning of the internal primary fuel 46 ensures that there is sufficient thermal energy provided after complete ignition of the external primary fuel 64 to avoid the ignition being extinguished even after the external primary fuel 64 is completely burned. The increased burn time of the primary fuels 46, 64 advantageously allows the operator more time to safely manually ignite the heat lance 1, position the heat lance 1, and initiate the flow of oxygen without the risk of the delay igniter cap 10 self-extinguishing, thereby avoiding insufficient or overly early ignition of the heat lance 1.

[0099] Combustion requires specific levels of heat (energy), fuel, and oxygen. In the case of a heat lance, the initial stage of combustion (ignition) requires specific ratios for each. The total amount of fuel available within the heat lance is predetermined by the size and design of the components. The amount of oxygen is variable and is determined by the oxygen pressure. The amount of thermal energy is variable and is determined by the external heat source used for ignition and the primary and secondary fuel loadings. Once combustion reaches a steady state, the combustion reaction generates sufficient thermal energy to continue indefinitely as long as sufficient oxygen and fuel (which are components of the heat lance itself) are available.

[0100] The combustion reaction is directly related to the amount of surface area of the fuel exposed to the required amount of oxygen and thermal energy. During the combustion process, increasing the surface area exposed to oxygen and thermal energy will enhance the ignition reliability and increase the efficiency of the combustion reaction throughout all stages.

[0101] In the case of the delay igniter cap 10 of the present invention, the ignition of the fuse 54 initiates the ignition and combustion process. As the protected portion 50 of the internal primary fuel 46 burns, the outer periphery of the secondary fuel 48 is ignited or overheated. This initiates the heat transfer process between the internal primary fuel 46 and the secondary fuel 48. During the almost instantaneous complete combustion of the unprotected portion 52 of the internal primary fuel 46, thermal energy is rapidly generated, causing the remaining portion of the secondary fuel 48 to ignite and / or continue burning. The thermal energy of the combustion of the secondary fuel 48 then ignites the components of the thermal lance 1 and initiates their combustion.

[0102] The positioning of the internal primary fuel 46 around the secondary fuel 48 increases the amount of thermal energy generated by the ignition and combustion of the internal primary fuel 46, increases the surface area of the secondary fuel 48 exposed to thermal energy, and increases the probability that the secondary fuel 48 will be properly ignited. This enables the use of secondary fuels 48 with higher ignition energy requirements, such as metal chips or flakes of aluminum, iron, titanium, magnesium, tungsten, and / or steel, steel wool, wood powder, or wood chips. Further, the heat transfer efficiency from the internal primary fuel 46 to the secondary fuel 48 is enhanced because the internal primary fuel 46 surrounds the secondary fuel 48 and the ignition of the unprotected portion 52 of the internal primary fuel 46 is almost instantaneous.

[0103] The positioning of the internal primary fuel 46 and the secondary fuel 48 also enhances the efficiency of heat transfer to the components of the thermal lance 1 for igniting the thermal lance 1. The components of the thermal lance 1 require a significant amount of thermal energy for ignition and combustion, and the proximity and focusing direction of the thermal energy generated from both the internal primary fuel 46 and the secondary fuel 48 are important. As shown in FIG. 5, the thermal lance 1 is inserted into the recess 58 within the housing 40 of the delay igniter cap 10 such that the distal end 14 of the thermal lance 1 contacts the secondary fuel 48 (in this case, specifically, the plug 62). The distal end 14 of the thermal lance 1 is also in very close proximity to the unprotected portion 52 of the internal primary fuel 46.

[0104] All of these benefits are achieved within a compact space, thereby reducing the size and overall footprint of the delay igniter cap 10.

[0105] The assembly of the delay igniter cap 10 can be accomplished as follows (FIGS. 6 - 14). A length of primary fuel in the form of a protected (sheathed) fuse with an unprotected portion 54a that serves as an ignition fuse is tightly wound around a mandrel to form a helix or coil (FIG. 6). The rotation of the helix is then joined to each other using any suitable joining material including, but not limited to, tape, plastic wrap, glue, rope or twine, wax, cardboard tubes, or metal, plastic, or rubber bands, clips, strings, and wires to form the external primary fuel portion 64a of the delay igniter cap 10 (FIG. 7). The joining material holds the helix / coil shape and provides additional combustible material for combustion.

[0106] The additional length of the fuse having the non-protected portion 52a is tightly wound around the mandrel to form a spiral or coil that serves as the internal primary fuel portion 46a (FIG. 8). The rotation of the spiral is then joined to each other using any suitable joining material including, but not limited to, tape, plastic wrap, glue, rope or twine, wax, cardboard tubes, metal, plastic, or rubber bands, clips, strings, and wires to form the internal primary fuel portion 46a of the delay igniter cap 10 (FIG. 9).

[0107] A steel wool roll is provided as the secondary fuel (FIG. 12). The steel wool can be grade 001. However, any grade of steel wool can be used, and finer grades are more preferred.

[0108] The steel wool roll is inserted into the central passage of the internal primary fuel portion 46a, and then the internal primary fuel portion 46a is inserted into the tube 40a (FIGS. 10 and 11).

[0109] The tube 40a is used as the housing of the delay igniter cap 10 (FIG. 13). The internal primary fuel portion 46a is inserted into the tube 40a and fixed in place using any suitable joining material including, but not limited to, tape, plastic wrap, glue, rope or twine, wax, cardboard tubes, metal, plastic, or rubber bands, clips, strings, and wires (FIG. 14). A recess for receiving the thermal lance 1 is left at the proximal end 60a of the tube 40a.

[0110] An additional steel wool roll is tightly packed and inserted into the proximal end 60a of the tube 40a. A tool can be used to gently compress the additional steel wool into the non-protected portion 52a of the internal primary fuel portion 46a. And the delay igniter cap 10 is ready for attachment to the thermal lance 1.

[0111] Any combination of one or more of the advantageous features of the delay igniter cap 10 can be incorporated into the blowback igniter cap 100 to form the combination igniter cap 200. An embodiment of the combination igniter cap 200 is shown in FIGS. 15 and 16. The combination igniter cap 200 includes features of both the delay igniter cap 10 and the blowback igniter cap 100.

[0112] The combination igniter cap 200 includes a proximal end 236, a distal end 238, a housing 240 having a sidewall 242 extending from the proximal end 236 to the distal end 238 and defining a passageway 244, and an internal primary fuel 246 and a secondary fuel 248 disposed within the passageway 244 of the housing 240. The internal primary fuel 246 and the secondary fuel 248 can be any suitable combustible material capable of ignition in the presence of oxygen, including but not limited to: pyrotechnic fuses; artillery fuses; metal powders of aluminum, iron, titanium, magnesium, tungsten, and / or steel; non-metal powders of wood, plastic, and / or synthetic materials; metal chips or flakes of aluminum, iron, titanium, magnesium, tungsten, and / or steel; steel wool, synthetic or organic foams; synthetic or organic textiles; and chemical mixtures of high-energy oxidizers and fuels. The internal primary fuel 246 and / or the secondary fuel 248 is porous, thereby allowing oxygen from the thermal lance 1 to flow from the proximal end 236 of the combination igniter cap 200 to the distal end 238 of the combination igniter cap 200 when the combination igniter cap 200 is attached to the thermal lance 1.

[0113] The distal end 266 of the housing 240 is substantially sealed and includes an opening 268 that allows the fuse 254 to pass therethrough. The distal end 266 of the housing 240 can be sealed in any suitable manner that substantially prevents oxygen flowing from the proximal end 236 to the distal end 238 of the combination igniter cap 200 from flowing out of the distal end 266 of the housing 240 of the combination igniter cap 200.

[0114] The plug or cap 270 can cover the distal end 266 of the housing 240 of the combined igniter cap 200 such that the distal end 266 of the housing 240 is sealed. The plug 270 can be made from any suitable combustible material that can be firmly fixed to the distal end 266 of the housing 240. Such materials include, but are not limited to, steel, stainless steel, iron, wood, cardboard, rubber, cork, plastic, tape, and other metallic, synthetic, or organic materials.

[0115] Alternatively, the distal end 266 of the housing 240 of the combined igniter cap 200 can be sealed by forming, crimping, welding, riveting, driving, or bending.

[0116] A recess 258 for receiving the hot lance 1 is provided within the proximal end 260 of the housing 240 of the combined igniter cap 200. An attachment ring 272 having a central opening 274 for receiving the hot lance 1 is provided within the recess 258 of the housing 240. The attachment ring 272 includes at least one opening 276 that enables oxygen to flow between the hot lance 1 and the housing 240 of the combined igniter cap 200 through the attachment ring 272.

[0117] At least one opening 276 within the attachment ring 272 can be provided as a hole or opening passing through the attachment ring 272, or the attachment ring 272 can be divided into parts and the opening 276 can be provided between the parts. When a plurality of openings 276 are provided, the openings 276 can be equally spaced around the attachment ring 272, for example, at 180° (two openings), 120° (three openings), 90° (four openings), or 45° (eight openings), or can be provided at different distances from each other.

[0118] The total surface area of the openings 276 within the attachment ring 272 is greater than any gap between the fuse 254 and the opening 268 at the distal end 266 of the housing 240, and thus most of the oxygen exits through the proximal end 236 of the combined igniter cap 200 and along the outer surface of the outer housing 16 of the thermal lance 1.

[0119] The attachment ring 272 can be made from any suitable material that enables attachment of the attachment ring 272 to the housing 240 of the combined igniter cap 200 and the outer housing 16 of the thermal lance 1. Such materials include metals, organics, plastics, ceramics, and rubbers. Attachment of the attachment ring 272 to the housing 240 of the combined igniter cap 200 and the outer housing 16 of the thermal lance 1 can be accomplished by any suitable method that ensures that the combined igniter cap 200 will not be removed from or move relative to the thermal lance 1 by the gas pressure of oxygen strongly affecting the sealed distal end 266 of the housing 240 of the combined igniter cap 200 or by the combined igniter cap 200 strongly affecting a solid object. Such methods include, but are not limited to, welding, crimping, compression, pinning, riveting, rubber inserts, metal inserts, springs, clips, pins, interlocking geometries, and corresponding screw connections.

[0120] Within the housing 240, the internal primary fuel 246 surrounds the secondary fuel 248. As shown in FIGS. 15 and 16, the secondary fuel 248 can be the central core within the passageway 244 of the housing 240, and the internal primary fuel 246 can be positioned between the sidewall 242 of the housing 240 and the secondary fuel 248 and provided in the form of a spiral or coil surrounding the secondary fuel 248. The spirals can be wound such that the rotations are spaced apart or such that the rotations of the spirals contact each other. By way of example, as shown in FIGS. 15 and 16, the rotations of the spirals within the protected portion 250 of the internal primary fuel 246 can be spaced apart from each other while the rotations of the non-protected portion 252 of the internal primary fuel 246 can contact each other.

[0121] The secondary fuel 248 may comprise two or more parts. For example, as shown in FIGS. 15 and 16, the secondary fuel 248 may comprise two or more substantially cylindrical parts extending longitudinally in the passage 244 of the housing 240. Alternatively, the internal primary fuel 246 may completely fill the space between the side wall 242 of the housing 240 and the secondary fuel 248, and / or the secondary fuel 248 may be a material that completely fills the space within the housing 240 defined by the internal primary fuel 246.

[0122] The fuse 254 can be manually ignited using a torch lamp, igniter, high-temperature element, or any other suitable ignition source, or can be self-ignited when the temperature or surface to which it is exposed exceeds the auto-ignition temperature of the fuse 254 for initiating combustion of the internal primary fuel. The combustion of the internal primary fuel 246 proceeds along a path through the internal primary fuel 246, and when the burning internal primary fuel 246 contacts the secondary fuel 248, the secondary fuel 248 is ignited and begins to burn.

[0123] The protective portion 250 of the internal primary fuel 246 can be separated from the secondary fuel 248 by a sheath that prevents and / or reduces cross-ignition between the internal primary fuel 246 and the secondary fuel 248 while still allowing the secondary fuel 248 to be heated by combustion of the protective portion 250 of the internal primary fuel 246. The non-protective portion 252 of the internal primary fuel 246 is in direct contact with the secondary fuel 248 such that ignition and combustion of the non-protective portion 252 of the internal primary fuel 246 ignites the secondary fuel 248. The protective portion 250 of the internal primary fuel 246 can also prevent the entire internal primary fuel 246 from igniting simultaneously. For example, when the internal primary fuel 246 is a spiral, as shown in FIGS. 15 and 16, the sheath surrounding the protective portion 250 of the internal primary fuel 246 suppresses ignition and combustion of the internal primary fuel 246 such that the ignition and combustion of the internal primary fuel 246 follows the path of the spiral and does not jump from one rotation of the spiral to an adjacent rotation of the spiral. When the combustion of the internal primary fuel 246 reaches the non-protective portion 252 of the internal primary fuel 246, all cross-ignitions of the rotations of the spiral in the non-protective portion 252 can occur simultaneously and ignite the secondary fuel 248.

[0124] The protected portion 250 of the internal primary fuel 246 can have a higher fuel volume than the unprotected portion 252 of the internal primary fuel 246. For example, when the internal primary fuel 246 is a spiral or coil, as shown in FIGS. 15 and 16, the protected portion 250 of the internal primary fuel 246 includes more turns of the spiral than the unprotected portion 252 of the internal primary fuel 246.

[0125] The housing 240 includes the internal primary fuel 246 and the secondary fuel 248 and can be made of any suitable combustible material having structural integrity for attaching the combined igniter cap 200 to the thermal lance 1. Such materials include, but are not limited to, phenolic resin, cardboard, plastic, low carbon steel, high carbon steel, stainless steel, and fiberglass.

[0126] As shown in FIGS. 15 and 16, the plug 262 of the secondary fuel 248 fills the passage 244 of the housing 240 and can function as a partition between the fuels 246, 248 of the combined igniter cap 200 and the distal end 14 of the thermal lance 1.

[0127] Optionally, an external primary fuel 264 may be provided between the fuse 254 and the internal primary fuel 246. The external primary fuel 264 may be continuous with and the same as or different from the internal primary fuel 246. The external primary fuel 264 may be attached to the outer surface of the housing 240 of the combination igniter cap 200. As shown in FIGS. 15 and 16, the external primary fuel 264 may be provided as a coil or spiral. The external primary fuel 264 may be surrounded by a sheath that prevents combustion of one portion of the external primary fuel 264 from igniting another portion of the external primary fuel 264 and / or the housing 240. For example, the sheath may prevent one revolution of the coil from igniting another revolution of the coil and / or the housing 240. Thus, when the fuse 254 ignites the external primary fuel 264, combustion proceeds along the coil of the external primary fuel 264 to the spiral of the internal primary fuel 246 contained within the housing 240 and then onto the secondary fuel 248 as described above.

[0128] Optionally, a tertiary fuel 280 may be provided between the central core 28 and the outer housing 16 of the thermal lance 1, where the tertiary fuel 280 is admixed with the components of the thermal lance 1. The tertiary fuel 280 may have a higher energy density than the secondary fuel 248 and / or a lower initial energy requirement for combustion than the components of the thermal lance 1. The tertiary fuel 280 may be, for example, compressed metal flakes, shavings, steel wool, wood, plastic, or non-metallic powders of synthetic materials, high-density synthetic or organic foams, or high-density synthetic or organic textiles. The tertiary fuel 280 is ignited by the combustion of the secondary fuel 248 and aids in the ignition of the components of the thermal lance 1.

[0129] The combination igniter cap 200 provides all of the advantages of both the delay igniter cap 10 and the blowback igniter cap 100.

[0130] While particular aspects of the invention have been described above for purposes of illustration, it will be apparent to those skilled in the art that numerous variations in the details may be made without departing from the invention.

Claims

1. An igniter cap for a thermal lance, the igniter cap comprising: A proximal end adapted to receive the thermal lance; A distal end; A housing having side walls extending from the proximal end to the distal end and defining a passageway; Internal primary fuel and secondary fuel disposed within the passageway of the housing; And comprising: At least a portion of the internal primary fuel is in contact with the secondary fuel; The distal end of the igniter cap is substantially sealed, and the proximal end of the igniter cap includes at least one opening such that when the thermal lance is received at the proximal end of the igniter cap, gas flows axially from the thermal lance, through the internal primary fuel and the secondary fuel, into the proximal end of the igniter cap, and the gas is then redirected by the sealed distal end of the housing to flow back through the internal primary fuel and the secondary fuel, through the at least one opening, and out along the outer surface of the thermal lance. An igniter cap.

2. The igniter cap according to claim 1, further comprising an opening at the distal end through which the fuse passes.

3. The igniter cap according to claim 2, wherein the total surface area of the at least one opening is greater than any gap between the fuse and the opening at the distal end.

4. The igniter cap according to claim 1, further comprising a plug covering the distal end of the igniter cap, thereby substantially sealing the distal end of the igniter cap.

5. The igniter cap according to claim 1, further comprising a mounting ring including or defining the at least one opening.

6. The mounting ring has a central opening for receiving the thermal lance, the igniter cap according to claim 5. **Claim 7** The at least one opening is a hole or an opening passing through the mounting ring, the igniter cap according to claim 5. **Claim 8** The mounting ring is divided into parts, and the at least one opening is provided between the parts, the igniter cap according to claim 5. **Claim 9** Further comprising a recess at the proximal end of the housing, the recess receiving the thermal lance such that or in contact with the distal end of the thermal lance adjacent to the internal primary fuel and / or the secondary fuel, the igniter cap according to claim 1. **Claim 10** Further comprising a porous barrier filling a part of the passage of the housing, the porous barrier serving as a partition between the internal primary fuel and / or the secondary fuel and the distal end of the thermal lance when the thermal lance is received within the igniter cap, the igniter cap according to claim 1. **Claim 11** The internal primary fuel surrounds the secondary fuel, the igniter cap according to claim 1. **Claim 12** The internal primary fuel and / or the secondary fuel is porous or includes openings to allow gas to flow from the proximal end of the igniter cap to the distal end of the igniter cap when the igniter cap is attached to the thermal lance, the igniter cap according to claim 1. **Claim 13** The secondary fuel is a central core within the passage of the housing, and the internal primary fuel is provided in the form of a spiral or coil located between the side wall of the housing and the secondary fuel and surrounding the secondary fuel, the igniter cap according to claim 1. **Claim 14** The internal primary fuel includes a protected portion separated from the secondary fuel by a sheath that prevents and / or reduces cross-ignition of the internal primary fuel with the secondary fuel, and an unprotected portion that is in direct contact with the secondary fuel. The igniter cap according to claim 1.

15. The protected portion of the internal primary fuel has a higher fuel volume than the unprotected portion of the internal primary fuel. The igniter cap according to claim 14.

16. The igniter cap according to claim 2, further comprising an external primary fuel provided on the outside of the housing between the fuse and the internal primary fuel.

17. The external primary fuel is surrounded by a sheath that prevents combustion of one portion of the external primary fuel from igniting another portion of the external primary fuel and / or igniting the housing. The igniter cap according to claim 16.

18. A thermal lance system, the thermal lance system comprising The igniter cap according to claim 1, and A thermal lance and The distal end of the thermal lance is received at the proximal end of the igniter cap. A thermal lance system.

19. A thermal lance system according to claim 18, wherein a tertiary fuel is provided in the thermal lance adjacent to the secondary fuel of the igniter cap.

20. The tertiary fuel has a higher energy density than the secondary fuel and / or a lower initial energy requirement for combustion than the components of the thermal lance. The thermal lance system according to claim 19.

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