MXPA98003362A - Exotermic and meto reactions - Google Patents

Abstract

Exothermic reaction mixtures are presented which are electrically ignited with a low cost sheet strip of two conductive strips separated by an insulating layer. One or more holes formed in the lighter or ignition trigger serve to create the spark plasma on one side and a vent plasma on the opposite side of the hole. The spark that has low energy requirements is enough to ignite and initiate the exothermic reactions for welding, casting and other uses. The lighter can be part of crucibles and reusable molds or molds, containers and disposable packages, or small detonators to light larger loads. The lighter may be immersed in or basically adjacent to the charge of the exothermic material. The hole or spark-forming holes is made and shaped by a punching in a simple and economical way. The lighter eliminates the need for initiating powders or ignition materials and flint guns for ignition

Description

i EXOTHERMAL REACTIONS AND METHODS DESCRIPTION OF THE INVENTION This invention relates generally to exothermic reactions and methods and more particularly to apparatuses and methods for initiating exothermic reactions that propagate on their own. Examples of self-propagating exothermic reactions are found in the CADWELD process, and in the Thermit process. CADWELD, is a registered trademark of Erico International, Inc., Solon, Ohio, U.S. ., and Thermit, eß a registered trademark of Th. Goldschmidt AG, Essex, Germany. Exothermic mixtures are basically a combination of a reductive metal and usually a transition metal oxide. An example is aluminum oxide and copper, which with ignition provides enough heat to propagate and sustain a reaction within the mixture. Generally, the molten metal product or the heat of this reaction is what is used to produce a desired result. The CADWELD process, for example, produces a mixture of molten copper and aluminum oxide or slag. Molten copper has a higher density than slag, and is usually routed through a mold to join or weld copper with copper or steel with steel. The aluminum oxide slag is removed from the weld or joint and discarded. Another common mixture is iron oxide and aluminum, where only the heat of the reaction is used, the heat can be used to melt the solder, for example. Mixtures of this type, do not react spontaneously and need a method to start the reaction. This method of initiation presents the generation of enough localized energy to allow the reaction to begin. Once the reaction has begun, it becomes self-sustaining and no longer requires more energy to proceed to completion. There are numerous combinations of reductive metals and oxides of transition metals that can react exothermically. These reactions and the energy required to initiate them vary greatly depending on the properties of the reactants and the conditions present. Twelve common mixtures are combinations of copper oxide and aluminum, iron oxide and aluminum. This invention concerns the initiation of exothermic reactions and apparatus or packing to use such reactions. At present, the most common method for making welds or joints with the CADWELD process, includes the use of separate graphite molds. The conductors or items that have to be brought together, are carefully cleaned and then placed in the appropriate place to project into a welding chamber in the graphite mold. The molds can include a crusher on top of the welding chamber connected to the welding chamber through a lid hole, the mold is then securely closed and locked with a crossed sear fastener and a metal disk is placed on the crusher above the lid hole. An appropriate amount of exothermic material is poured onto the crushable at the top of the disc, and a traditional initiating material or powder which is essentially a finer exothermic material, is sprayed onto the upper part of the soldering material, then the Cover the mold and start the reaction using an obsidian lighter. The starting powder or material sprayed on the top of the exothermic material has a low ignition temperature and is easily ignited by the obsidian gun, while the obsidian gun can not normally ignite the exothermic material directly. When the exothermic material is ignited, the molten metal phase separates from the slag and flows through the metal disk. Then, the molten metal is directed through the hole to the welding chamber and to the conductors to be joined, once the metal has solidified, the mold is opened and the slag is separated from the welded joint, the mold is cleaned and it is re-prepared to be used again in the next connection. Due to the low ignition temperature of the initiation powder and the deficiencies in handling and transportation, much effort has been made to find a reliable and low cost alternative ignition system for the exothermic material. Various electrical systems have been designed, ranging from simple sparking spaces to wires or bridge leaves and even exothermic devices, such as cigarette lighters. Such efforts are appreciated, for example, in the above US patents 4,881,677; 4,879,952; 4,885,452; 4,889,324 and 5,145,106. For a variety of reasons, but basically because of the power requirements, dependence and cost, such devices have not succeeded in replacing the standard initial powder combination, obsidian gun, to cause self-propagating exothermic reactions. The packaging of the system is also important, many of its applications are carried out outside or in the field, and it is important to transport it and its ease of use. For example, nobody wants to charge a car battery to be used as an ignition system. Also the system should be able to be used with a light weight, be easily used and with clean or preferably disposable components, an ignition system for such materials, it should be able to produce approximately thirty (30) joules of energy, the system should not require a special shipping or labeling classification that is now required in some places with certain starting materials or powders. The system components must be user-friendly to be portable and operable with just one hand, the system must be easily transportable to difficult work areas or confined or full spaces. The components of the system must weigh less than 1.5kg, or approximately the weight of a partially filled official suitcase, it is important that the ignition is reliable and repeatable without frequently requiring new batteries or frequent surcharge and must be economical in use and manufacture. It would also be advantageous if the ignition system did not use projecting wires or wires to which a power source needs to be connected. The power can be connected to such wires by crocodile grips, for example, one for each wire, the wires tend to bend, slip, get tangled in things or break, and easily short circuit, often the lack of operation is simply the grip connection, and this requires testing or repositioning of the grabs or wires before the problem is located. It would be desirable if wires were not used and a suitable connection could be made with a single wire. The reaction initiation system of exothermic materials includes a power source to produce an increase in voltage and a lighter comprising two strips of metal sheet separated by an insulating layer. The lighter includes one or more distortions formed and strategically placed in the shape of one or more perforated holes. It has been found that a relatively low voltage applied to the leaf strips will create a spark plasma of sufficient shape and projection to ignite almost all of the adjacent exothermic mixture, and maintain the reaction propagated to completion. The hole is formed by a small conical point bore, the conical tip shape makes the hole like a horn and the opening at the small end of the horn acts as a vent. The power source can be a capacitor discharge unit, with battery power that produces the voltage to be sent to the metal foil strips by two electrodes that form the opposing gripping surfaces of a gripper of the spring type of grippers for clothes, which are simply gripped on a projecting end of the sheet metal strip, with a strip of sheet in contact with an electrode. This maintains the required polarization, the battery can be relatively small, easily replaceable and rechargeable. The capacitor discharge unit only needs to create a voltage of approximately thirty (30) joules for most applications, and this is sufficient to create the plasma formed and ventilated from the spark in the interruption or hole. The lighter unit is preferably thin strips of conductive sheet that are separated by a thin layer of paper insulation adhered to the sheet with thin layers of adhesive, so that the layers do not separate easily and there are no air spaces or bubbles . Preferably, the insulation extends beyond the sheet, particularly at the ends, so that no spark is present at the edges or at another location other than the strategically placed interruption. He Adhesive can be conductive to improve the flow of current through the metal sheet. The entire assembly including the conductive sheet, the adhesive and the insulation, may only be a few tenths of a centimeter in thickness, and the strip assembly may be bent, folded or twisted to some degree without damaging its integrity and function. The selection of the metal or type of sheet depends on the application, since the formed and ventilated plasma that produces the spark discharge in the inrruption, includes controlled metal splashes and fusion of the sheet and since the lighter in some applications will be consumed at least partially by the reaction, it is important that the metal of the sheet is compatible with the reaction, so for the welding of copper, it would be a suitable sheet material, also the paper and adhesive are selected not to contaminate the exothermic process . Although the lighter assembly has many applications, in connection with reusable crucibles and molds designed to contain and direct the reaction and reaction products, a preferred form is constructed in a self-contained, disposable package of exothermic material. The package can be placed on a reusable or disposable mold, and the lighter assembly can be unfolded or folded to extend or project from the package. The lighter is connected to the power source and the reaction starts. A disk at the bottom of the package is melted by the reaction and the molten metal runs inside the reusable or disposable mold. The power source is disconnected, and the package is discarded when cooled. In some embodiments, the lighter may include two or more holes or interruptions that create spark plasma, if the holes are the same size they will light concurrently. Such lighters can be used for large volumes of exothermic materials to obtain multiple point ignition, if the holes vary in size an ignition can be obtained in sequence. Multiple hole lighters can be used for higher loads or redundancy. In addition, to the lighter and methods for making the lighter, the invention also relates to the ignition methods presented, as well as the applications and packaging for using the lighter, all of which economically eliminates the use of initiation powder and similar materials , as well as the flint gun lighter. In order to carry out and obtain the aforementioned objects, the invention comprises the features that will be described more fully and will be pointed out especially in the claims. The following description and drawings set forth in detail certain illustrative embodiments of the invention, but indicate only some of the different ways in which the principles of the invention may be used. DESCRIPTION OF THE DRAWINGS FIGURE 1 is a schematic illustration of the power source and lighter assembly; FIGURE 2 is a schematic illustration of the metal foil strips of the lighter that are assembled with intermediate insulation; FIGURE 3 is a schematic illustration of the lighter assembly but before the hole is drilled and shaped; FIGURE 4 is a schematic illustration of edge elevation showing the cone-tipped drill almost to enter the lighter; FIGURE 5 is a similar schematic illustration drawing the perforator forming the hole; FIGURE 6 is a similar schematic illustration showing the hole formed; FIGURE 7, is a schematic illustration of a lighter with the hole placed more in the center; FIGURE 8, is a schematic illustration of the fusion that takes place around the hole in an intermediate phase of the ignition; FIGURE 9 is a schematic illustration of the plasma spark energy created showing the conical shape of the plasma energy on one side and the ventilation plasma on the other side; FIGURE 10 is another somewhat larger view showing the shape of the spark plasma of the ventilating plasma and the fusion taking place, all submerged in an exothermic reaction mixture; FIGURE 11 is an exploded view of the lighter assembly of the present invention extending diametrically through a disposable container or crucible to be placed on a reusable mold; FIGURE 12 is a section through the assembly of FIG. 11; FIGURE 13 is a view of a lighter extending through the wall of a reusable mold and crucible; FIGURE 14 illustrates the lighter placed under a hanging cover of a reusable mold and crucible; FIGURE 15 illustrates the lighter placed between a lid of the type used with one or more smoke and particle collector filters; FIGURE 16 illustrates the lighter used with a mold and disposable crucible; FIGURE 17 is a perspective view of a container of the detonator type of exothermic material with the lighter e extending across the end; FIGURE 18 is a diametrical section of the container of FIG. 17; FIGURE 19 is an illustration of a smaller detonator that is used to ignite a larger reaction; FIGURE 20 is a view of a disposable package but the lighter is not submerged in the exothermic material, but placed parallel to the cap and the hole that generates the spark plasma is substantially adjacent to the upper surface of the material 1; FIGURE 21 is a sectional view of another type of disposable package used with another type of disposable mold; FIGURE 22 is an illustration of a large crucible with three lighters placed above and basically adjacent to the upper surface of the exothermic material; FIGURE 23 is an illustration with FIG. 22, but showing a single lighter with multiple holes; FIGURE 24 is a schematic illustration of a multi-hole lighter with holes of a common size; FIGURE 25 is a similar schematic illustration of a multi-hole lighter with holes of increasing size; and FIGURE 26, is a schematic illustration of another form of lighter that can also be used where redundancy is desired. Referring initially to Fig. 1, a capacitor discharge unit is generally illustrated at 30 to create the voltage for igniting the igniter assembly 32, for the exothermic material, the discharge of the capacitor 30, includes one or more batteries 33, connected to an inverter or oscillator 34, which converts the direct current of the batteries to a high frequency alternating current. The output of the inverter then passes through a step-up transformer 35, which increases the voltage, the high-voltage alternating current passes through a rectifier 36, which can be full-wave or half-wave to convert the alternating current to another. Once direct current is applied, then the direct current charges the capacitor 37, when an interrupter 38 is closed, a voltage shock is created between the conduits 39 and 40, the switch 38, it can be a mechanical or solid-state switch and if this last, the switch can be closed by the threshold ignition circuit 41. The guides 39 and 40, schematically shown, are connected to the semi-round, projecting electrodes 43 and 44, extending transversely over the inside of the jaw of a loaded clamp. with a clothes type spring or a crocodile pin, as shown under figure 46. Referring additionally to Figs. 2-6, it is appreciated that the igniter assembly 32, comprises two strips of conductive metal sheet 50 and 51, separated by an insulation layer 52, the method for manufacturing the lighter is illustrated in sequence in Figs. 2-5. Since the lighter will normally be consumed in the exothermic reaction, it is important to select materials for the lighter compatible with the materials of the exothermic reaction. In the CADWELD process, where the copper conductors are welded, the preferred sheet metal material is copper. The preferred insulating material can be paper, and the entire thickness of the assembly can be only a few thousandths of an inch. It will be appreciated, however, that for other applications other metals or conductive sheets may be used in conjunction with other insulating strips. The thin layer of paper insulation serves two purposes. It provides an insulating barrier between the two strips of the copper foil and also provides a deflective barrier for both heat and energy, once the igniter is turned on or the reaction is initiated. The outer sheet layers 50 and 51 are attached to the thin paper intermediate insulation layer by a minimum amount of conductive adhesive which can be placed on the inside of the copper sheet strips. The adhesive allows the copper strips to be firmly fixed in the paper, while the air spaces are eliminated, and the conductive nature of the adhesive improves the flow of current along the sheet metal strip. The sheet layers and the insulation can be passed through the shrinkage of the rollers, to ensure adhesion and proper removal of the air spaces as seen in Fig. 2. When the lighter layers are assembled as seen in Fig. Fig. 3, the insulation 52, is preferably projected slightly beyond the ends of the sheet strips, such projections are shown with the numbers 55 and 56. The projections are somewhat exaggerated in the schematic illustrations and may be a small fraction of an inch or a few millimeters. Once the lighter is assembled as seen in Fig. 3, an interruption is formed in the lighter to provide a source for the discharge energy. This interruption is in the form of a conical hole that is formed by the perforator 58, which has a relatively sharp conical tip 59.

As seen in Fig. 5, the perforator or tapered penetrates the strip and the tip 59 projects through the strip assembly to project slightly from the other side as seen at 60. As seen in Fig. 6 , when the conical is removed a hole 62 is formed, in the strip lighter having the conical conical configuration, the hole on one side, has a large end 63, and on the other side has a small end of ventilation 64. The hole passes completely through the strip assembly and the hole formed is in the shape of a horn that is hazelnut towards the large end 63. The hole can be located at any desired point along the strip and in the manner presented in FIG. Fig. 6, is placed at one end. In Figs. 7, 8 and 9, the hole shown at 66 is located in the center of the strip end to end and centrally between the side edges. Also as described below, more than one hole can be made and its size may vary. The illustrated hole is not to scale and the diameter of the large end of the hole can vary from a fraction of a millimeter to approximately two millimeters. The angle of the cone may also vary, as compared to that illustrated to provide or obtain the conical or horn configuration that provides a formed spark plasma. Being a perforation, the hole has perforation characteristics that distort the linear nature of the assembly by providing slightly creased or wrinkled edges and attenuated insulation in the hole. When the reaction has to be initiated and the cigarette lighter strip assembly 32, it must be turned on it must be turned on it is connected to the discharge unit 34, of the capacitor by joining the clip 46, on the projecting e tre trem of the lighter assembly. When the capacitor energy is released, the initiation of the exothermic reaction occurs in milliseconds. Although the precise mechanics of the phenomena is not known, it is believed that the phenomena can be expressed by the following sequence of events, and as particularly illustrated in FIGS. 7, 8, 9 and 10. In the sequence of the ignition, the energy is released from the capacitor and enters the two copper strips 50 and 51, each receiving a pole of the discharge, that is, one negative and one positive . The tapered hole 66, through the sheet and strip assembly, acts as an interruption or resistance point and begins to heat up rapidly. So quickly that basically there is no time for the heat to dissipate to the surrounding materials. Eventually there will be enough heat available to cause a rapid melting of the entire thin edge of 360"from the hole at the edge of the conical hole This is presented according to the formula I2R, where I is the current and R, is the resistance.The melted edge in the intermediate phase as seen in 68, in Figs 8 and 10, increases the resistance thus increasing the speed of additional heating.The copper melt, occurs at a temperature of 1083 * C The phenomenon occurs in such a short time that the fusion phase is unable to move, and the continuous heating forces the molten copper to become steam, this occurs for copper at a temperature above 2571 ° C. The gas phase Increases the resistance in the air 1 increases 1. The steam begins to expand but continues to draw current until it begins to present an electric arc.The spark plasma or arc can reach temperatures in excess of 5,000 °, the electric arc f It lumps the gas phase to an ionization point that begins to reduce the resistance very quickly, which increases the amount of current that enters the area. The increase in current to the vapor region, produces a heating or super heat to expand the vapor which forces the vapors to expand rapidly producing a shock wave resulting from spark plasma as schematically shown as top cone 70, in the Fig. 9 and 10. In such Figs., The lighter is dipped which may be in the illustrated granular form 72, on both sides of the lighter. The conical shock wave, however, expands with reduced force due to the presence of the vent hole or smaller on the other side of the lighter. This vent or smaller end of the hole produces a smaller spark plasma as seen at 74, reducing the extension and force of the shock wave cone 70, thus reducing the disturbance of any exothermic material 72, surrounding or near before the initiation of the reaction. A force that is too large or too sudden can remove or extinguish some types of exothermic material with respect to the heat of the spark plasma.

The shock wave carries molten copper as seen at 76, in Fig. 10, from the molten circumference 68, of the conical hole. The copper 76 extends outwardly from the circumference of the conical hole while the vent hole provides the spark plasma 74, and the energy transfer in the opposite direction. The combination of superheated steam, the release or release of molten copper in the shock wave and the electric arc socket provides a substantial emission of energy and a multiple point ignition of the exothermic material 72. Referring now to Figs. 11 and 12, the use of the lighter of the present invention is illustrated in an exothermic welding apparatus, such as the CADWELD process, for welding rods or cables together, for example. The apparatus illustrated in Figs. 11 and 12, comprises a crucible or container 80, disposable and a reusable mold of two parts 81. The mold assembly 81, is horizontally separated as seen at 82, in upper and lower mold parts 83 and 84, made of a refractory material, such as graphite. The separating faces have recesses forming sleeve passages 85 and 86, which lead to an enlarged welding chamber 87. The parts of the mold assembly can be gripped together in the separator plane and opened by a traversed fastener grip which is not sample. The upper mold part 83 is provided with a recessed seat 89, axially aligned with a smaller vertical hole 90, communicating with the welding chamber 87. The sleeve passages are adapted to receive ends of cable or bar that they are projected in the welding chamber and they have to be welded together by the illustrated apparatus and process. The disposable pack 80 includes a correct amount of exothermic material as seen at 92, in Fig. 12. This exothermic material is supported on a metal disk 93, which closes the hole 94, at the bottom of the package, which hole is aligned with the upper hole 70, when the package is assembled with the mold. The disposable package is in the form of a refractory cylindrical container 95, and a lid 96, has a central ventilation hole 97. The interior of the package provides a chamber of crucible 99, ending with conical seats in the bottom, the lowest of which supports the metallic disk 93.

E running diametrically through the top of the cylindrical package there is a lighter assembly strip 32, which includes the formed hole 62, in the upper center of the exothermic load 92. The lighter assembly extends through vertical slots 101 and 102, on the package wall and the end 103, projects substantially beyond the outer side of the package. The upper level of the exothermic charge seen at 104 is above the lighter strip 32, so that the hole 62 is submerged in the upper portion of the exothermic material. Disposable package 80, of Figs. 11 and 12, contains the precise amount of exothermic material and the package components can be formed from a variety of refractory materials, such as baked ware, molded sand or glass, for example. The package is disposable after use. The container can be formed with the lighter assembly put on, filled with the required amount of exothermic material and then closed by the lid 96, to form the complete package. The extended end 103 of the lighter can simply be folded so that it lies flat against the package wall and then wrapped around the whole. When the package is used it is simply unwrapped and placed in the seat 89, and the shaft 103 extends so that it projects radially as shown. Clamp 46, of Fig. 1, is then attached to projecting end 103. When the exothermic reaction is initiated, it will start at the top of the material charge and move downward by melting disk 93, to allow the molten metal to run into the metal welding chamber 87, by welding the end of the cables or bars to each other. Any slag formed by the reaction rises upwards and can be removed from the weld. When the package is cooled, it is simply discarded, and the mold parts 83 and 84, are opened to remove the welded rods or bars. The mold parts are cleaned to be reused with another disposable package. In the embodiment of Fig. 12, the lighter extends diametrically completely through the exothermic material charge and is submerged. There are, however, a number of ways in which the lighter can be placed with respect to the exothermic material contained in the crucible, either a disposable package or a reusable mold.

Referring to Figs. 13-15, a number of ways are illustrated of how the lighter can be mounted with respect to the exothermic material contained in a crucible that is part of a reusable mold. In Figs. 13-15, the molds are vertically separated, and each half of the mold contains the cavity and passage pattern illustrated in the form of semi-circular recesses. When the two halves of the mold are joined together, the complete mold is formed. Each mold assembly includes a welding chamber 106, sleeve passages 107 and 108, a lifting chamber 109, at the top of the brazing chamber, a lid hole 110, communicating with the bottom of the crucible 111, and the lifting or welding chamber including the last the tapered seat at the bottom for the metallic disk 112, closing the bottom of the crucible in the hole of the lid where the load of the exothermic material 114. is located. In the Fig. 13 and 14, the upper part of the assembly is provided with a hinged refractory lid 116. In Fig. 13, the lighter assembly shown at 32, extends only through a wall of the crucible chamber and through an insulator 118, which can be made of paper. The lighter has a projecting end 119, which extends from the outside of the insulator and the hole or interruption 62, is below level 120, of the exothermic material 114. The ignition hole is nevertheless in the upper central portion of the load of the exothermic material. In Fig. 14, the lighter 32, extends through the insulator 122, which may be paper at the edge of the crucible below the hinge cover 116. The lighter assembly projects beyond the insulator as seen at 123, and it is twisted at 124, so that hole 62 is below the surface 120, of the exothermic material. In this embodiment, the assembly has projection as a main horizontal plane rather than as a vertical plane as seen in Fig. 13. However, the lighter strip is bent, so that in hole 62, the main plane ße extend vertically. In the reusable mold of Fig. 15, there is a cover 128, which extends telescopically over the assembly and supports one or more filters 129, adapted to retain fumes other undesirable byproducts of the exothermic reaction. The charge of exothermic material 114, however, can be ignited by the lighter 32, which passes through an insulator 131, between the lid 128, which contains the filter and the upper side of the crucible. The insulator 131, is stepped to provide the zigzag configuration shown that fits between the mold and the lid. The lighter can be bent to fit through the insulator and includes the projecting horizontal projection 132, and a twisted section 133, inside the insulator that allows the inner end to project downward in a different plane, so that the hole or interruption 62 , is below level 120, of the exothermic charge. Filter units for smoke are sold by Erico International Corporation of Solon Ohio, under the trademark EXOLON, which allows exothermic welding to be carried out in sensitive environments or 1 impios In any case, the igniter or initiator of the ignition of the present invention can be adapted immediately to extend through the walls of the reusable molds or between the ring caps of the crucibles, and the illustrated insulators or packages not only support the assemblies. of ignition either projecting through the walls as seen in Figure 13, or being twisted to project through the hoop down into the exothermic material. In each case the ignition is obtained by attaching the clamp 46 to the projecting ends 119, 123 or 132. As illustrated in FIG. 16 the ignition assembly 32 projects through the wall 138 of a disposable mold 139. Mold body can be made of a refractory material such as ceramic, a bonding sand, or glass, for example, and include a crucible upper chamber 140 and a lower welding chamber 141 with a shoulder 142 between the chambers supporting a metal disk 143 containing a load 144 of exothermic material in the chamber melting pot. The disposable mold is provided with a lid 146. The bottom of the mold is provided with a keyhole sleeve passage 148. The passage can accommodate the upper part of a bar 149 and a cable 150 for there welding. The lighter assembly can be installed in the disposable mold during the forming process, and can subsequently be inserted through a formed slot. The interior of the lighter assembly has the hole or interruption 62 positioned centrally in the upper center section of the exothermic charge, and the The outer side of the assembly is radially projected as indicated at 152. For packing and shng, the lighter can be folded or folded along the dotted line indicated at 153 to be flush against the outside of the mold wall. The lighter can be bent without compromising its integrity. When the package is opened, the lighter simply straightens up to project itself in the illustrated manner. The package is placed on the and the cable, and the clip 46 grips the projecting end of the lighter assembly. The capacitor discharge unit upon ignition produces the ignition of the exothermic material by causing the ignition of the spark plasma described above. The ignition of the exothermic material melts the disk 143, and the molten metal drips into the welding chamber to weld the two parts together. After welding, the mold can be left in place or it can be removed with a hammer. The lighter of the present invention can be used with what is usually called a detonator. The detonators are sometimes referred to as small charges of exothermic material which in turn were used to ignite larger loads. The detonator can cast molten metal spray on the surface of the larger exothermic material which is sufficient to initiate the main exothermic reaction. A detonator is shown in Figures 17 and 18 by pointing to the numeral 160. The detonator 16 comprises a refillable disposable cup-shaped container 161 that includes a cylindrical wall 164 of exothermic material, and the open end ring of the cup. it closes by a thin sheet metal hood 165. The lighter assembly 32 projects through the end wall 163, and the hole or interruption 62 is embedded in the exothermic material charge. The free or connecting fluid 167 is simply projected axially from the container through the wall 163 and the clip 46 can be connected immediately to the projecting end 167. When the exothermic material is ignited, it quickly burns through the hood 165 transmitting molten metal and other products or the reaction itself that can in turn be used to ignite a larger load of exothermic material. In Fig. 19 there is a larger charge of exothermic material 170 contained in a major crucible 171. A detonating igniter for such a charge is shown with 172 and comprises a smaller charge of exothermic material in a consumable container 174, the bottom of which closed eßta by a thin sheet metal hood 175. The lighter assembly 32 projects through the wall of the consumable container with the hole 62 inside the container. The projecting end 177 allows the capacitor to discharge upon engagement with the clip 46. Upon firing, the contents of the detonator melt the hood 175 and literally bathe the top surface of the main amount of exothermic material 170 with a super hot molten metal sprinkler as described in FIG. indicates at 178. This in turn ignites the greater amount of exothermic material. In Figure 20 there is illustrated an exothermic material charge 180 within a disposable container 181 supported on the consumable disk 182. The upper level of the load 180 is 183. The lighter assembly 32 for the exothermic material 180 is placed mainly in a horizontal plane and is folded in zigzag as seen in 185 and 186 to fit over the ring of the container and under the lid 187. The lighter is the thin case to fold in the indicated manner without compromising the lighter or the connection between the container and its lid. The central portion of the lighter may bow slightly downward as seen at 189 to place the hole 62 slightly above level 183 and in the center of the load. It is noted that the large end of the hole 62 is directed downwards and is tightly above or almost adjacent and almost contiguous with the upper level 183 of the exothermic charge. The lighter end 190 projects beyond the container to allow the capacitor decharge unit to be connected there. The characteristics of the spark plasma of the plasma discharge are sufficient to ignite the exothermic material even when the hole is not submerged in the material. In Figure 21 a disposable refractory container 192 is illustrated which includes inclined metal guide sleeves 193 and 194 projecting to a welding chamber 195. The sleeves allow cables or rods of different sizes to be inserted for welding without regard to the sealing of molten metal. the upper part of the disposable mold includes a ring 196, and the disposable container 197 is placed on that ring. The container 197 is generally similar to the container 80 seen in Figure 12, but includes an annular bottom pouring nozzle 198 adapted to project into the upper part of the mold 192. An annular flange 199 surrounds the nozzle allowing the container 197 is placed in the mold as illustrated. Like the container 80, the igniter assembly 32 extends diametrically through the wall of the container and the hole 62 is positioned within the exothermic material charge at the upper center. Referring now to Figure 212 there is illustrated a large crucible 171 containing a large load of exothermic material 170. The lighter assembly shown in the general 200 includes three sets of lighter strip 201, 202, 203 projecting through the mold wall 204. . The end of each set is provided with a hole or interruption as seen in 205, 206, 207, respectively. The lighter strip assemblies are interconnected by a conductive section 209 having a projecting vane 210 to which the capacitor discharge unit is connected. The interrupters or holes may be placed almost adjacent to the upper surface of the material or may be immersed in the material. If they are on top of the material, the large ends of the holes will look down. In any case, the lighter of Figure 22 provides a basically concurrent multipoint ignition for the large load of exothermic material. In FIGS. 23 and 24, another multipoint lighter assembly 212 is illustrated. The lighter assembly 212 extends through opposing walls 213 and 214 of the crucible 171 and projects from both as indicated in 215 and 216, respectively. . the lighter eßta provided with three holes 218, 219 and 220 which are the same size, and which are equally spaced from each other. In the mode of Figure 23, the greater e tre ther of the holes looks down or towards the exothermic material charge. The capacitor discharge unit attached to any projecting end of the igniter assembly will provide three basically concurrent ignition points for the exothermic load 170. Referring additionally to Figure 24, it is seen that strategically placing more than one hole in the body of the igniter, and when making holes with identical characteristics, including shape and size, sufficient energy can be applied to ensure that each hole or seat acts as a spark plasma charge igniting or simultaneously dissipating. However, with an ignition of multiple points as illustrated in Figures 23 and 24, higher energy levels are required when each hole or hole uses an equal fraction of the energy. In Figure 25, it illustrates a lighter assembly 225 having three different sites or holes 226, 227, 228, holes that are not of the same size and character. A lighter such as the one seen in Figure 25 can be used to provide a reliable factor. Thus, if the holes differ in size and shape, then the electrical resißence in each hole or hole will determine which will take the energy for initiation. With the clamps attached at the end of the 230 the smallest hole would be the first to light. The other charges on the lighter will remain intact without any energy discharge. Therefore, the lighter acts normally as a lighter of a stick or place. However, if the discharge f | ¡1 | in turn the exoteric material so that by disturbing the material indicated above, the breath has discharged and is sufficiently destroyed, eliminate any contact between the two sheets of copper. This seat will not be able to charge a second time. However the other places are still intact and can download. Recharging the capacitor and detaching the current in the lighter assembly a second time will result in another place discharging into the same lighter. Again, the amount of resistance in each location determines which site to download the next time. the sequence can continue until the lighter is sufficiently destroyed or the exothermic reaction is initiated. With reference to Figure 26, another form of lighter assembly at 232 is illustrated, which includes two holes 233, 234. The holes 233 and 234 may have identical identical character and identical shapes. However, the sheet lying in front of the observer is provided with a space 235. The clamps 46 of the capacitor deepening unit can be placed at the end 237 or 238 to obtain the charge in place of the hole. If the discharge fails in a hole in the ignition of the exothermic material, the clamps can simply be placed on the other end of the strip assembly, and the capacitor discharge again fired. It can be seen that a low cost sheet strip lighter is provided for the exothermic material that a wide range of applications for exothermic welding, casting and other uses, the lighter can be part of crusalee reusable and mold, or disposable packs , disposable container and mold, or use in small detonators to light larger loads. The lighter can be immersed in an almost adjacent to a load of exothermic material. The lighter eliminates the need for initiating powders or ignition materials or flint guns. Although preferred examples have been presented, they have been exemplary and are not limiting for the many changes and modifications evident in the spirit of the present invention.

Claims (37)

1. REVINDICAE í a NI i 1.- A method to cause the ignition of exothermic material comprising the steps of forming a charge of such material, placing a metal foil lighter that produces a spark plasma formed, in ignition relation with the load, and apply a voltage on the lighter that is sufficient to create the sparkle and at the same time to cause the ignition of the load.
2. 2. A method according to claim 1, wherein the lighter comprises insulating sheet layers.
3. 3. A method according to claim 2, wherein the metal foil lighter includes a distortion that creates the formed spark plasma.
4. 4. A method according to claim 3 wherein the dieto- tion attenuates the isolate.
5. 5. - A method according to claim 2, wherein the lighter includes a hole that creates the spark plasma.
6. 6. A method according to claim 5 wherein the perforation is punched.
7. 7. - A method according to claim 5 wherein the perforation has the shape of a horn.
8. 8. A method according to claim 7 wherein the perforation is generally conical in shape and ventilated.
9. 9. A method according to claim 5 wherein the perforation is generally conical in shape and ventilated.
10. 10. A method according to claim 5 wherein the perforation is formed to traverse the spark gap a sub-substantial distance at the time of a direction.
11. 11. - A method according to claim 1 wherein the eista caßi leaf lighter adjacent to the load.
12. 12. - A method according to claim 1 wherein the blade lighter is submerged in the load.
13. 13. A method according to claim 1 wherein the cylindrical load and the igniter or igniter cage extends diametrically in the load.
14. 14. A method according to claim 1 wherein the cylindrical load and the lighter extends generally axially with respect to the load.
15. 15. - A method according to claim 1 wherein the charge eßta contained in a dry pack.
16. 16. A method according to claim 1 wherein the charge eeta contained in a reusable package.
17. 17. A method according to claim 1 wherein the charge eßta contained in a detonator.
18. 18. An igniter or ignition trigger for exothermic material comprising a strip of metal sheet, a dietoreion on the strip that functions to create a sufficient playema of light to ignite the material, and means to apply a voltage to the strip. to create the spark plasma in that distortion.
19. 19. A lighter according to claim 18 wherein the lighter comprises insulated sheet layers.
20. 20. A lighter according to claim 19 wherein the distortion attenuates the insulation.
21. 21. A lighter according to claim 18 wherein the distortion includes a perforation.
22. 22. A lighter according to claim 21 wherein the perforation is punched and shaped.
23. 23. A lighter according to claim 21 wherein the perforation has a generally conical shape.
24. 24. A lighter according to claim 21 wherein the perforation creates an opening of less than approximately 2 mm in any dimension.
25. 25. A lighter according to claim 21 wherein the perforation is shaped to create a chiepa plasma on both sides of the sheet.
26. 26. A cigarette lighter according to claim 21, wherein the perforation is formed to transmit the spark plasma a subetancial distance in at least one direction.
27. 27. A lighter according to claim 18 including in combination a load of exothermic material and wherein the distortion is adjacent to the load.
28. 28. The combination according to claim 27 wherein the distortion is emersed in the charge.
29. 29. The combination according to claim 27 wherein the load is cylindrical and the lighter extends diametrically in the load.
30. 30.- the combination according to claim 27, wherein the load is cylindrical and the lighter extends axially to the load
31. 31. The combination according to claim 27 wherein the load is contained in a reusable mold.
32. 32. The combination according to claim 27 wherein the load is contained in a disposable package.
33. 33. The combination according to claim 32 e / i where the package includes a mold.
34. 34.- A lighter according to claim 18 which includes a single seat to create the spark plasma.
35. 35. A lighter according to claim 18 wherein the lighter includes multiple seats or places to create the spark plasma.
36. 36. - A lighter according to claim 35 wherein the multiple seats are holes that have basically the same characteristics.
37. 37. A lighter according to claim 35, wherein the multiplex seats are holes with unequal characteristics. R E S U M E Exothermic reaction mixtures that are electrically ignited with a low cost sheet strip of two conductive strips separated by an insulating layer are presented. One or more holes formed in the lighter or ignition trigger serve to create the spark plasma on one side and a vent plasma on the opposite side of the hole. The spark that has low energy requirements is sufficient to ignite and initiate the exothermic reactions to weld, strain and other ueoß *. The lighter can be part of crucibles and mold reusable or molds containers and packages of hierchables, or small detonators to light larger loads. The lighter may be immersed in or basically adjacent to the charge of the exothermic material. The hole or spark-forming holes is made and shaped by a punching in a simple and economical way. The lighter eliminates the need for initiating powders or ignition materials and flint guns for ignition.