EP0469458A1 - Electric igniter for detonators - Google Patents

Abstract

Electrical detonator for detonators (10) with a base charge (14) made of highly explosive material, in which the ignition means (20) has a connecting piece (40) made of energetic material, such as a pn junction or an LED chip, which is in a sealed Plastic or glass housing (50) is encapsulated. By applying a voltage pulse of more than 500 V, the connecting piece (40) is excited to form an electric arc, which forms a plasma in an exothermic reaction at high temperature and high pressure, which breaks out of the housing in a direction-controlled manner and with increasing pressure and temperature in an intermediate space (30) acts on the base charge (14) and detonates it. <IMAGE>

Description

The invention relates to an electrical detonator for detonators.

When using explosives for the excavation, strip mining in the mine and other earthmoving work, it is common to distribute several charges of a relatively cheap explosive in the area to be detonated and to use detonators to cause the various charges to explode. In this way, a relatively cheap explosive material can be used to lift and move the area to be blasted.

The primers or primers consist of highly explosive material; however, they are relatively insensitive to normal detonation methods and require an explosive device to initiate them. The detonation of the primer charges then initiates the cheap explosive charges.

The primers can be initiated by a non-electric detonating cord that is routed through the area to be detonated. However, an easier to control system uses electrically ignited detonators as primers. These electrical detonators are usually cylindrical metal containers or cartridges that have a lower part or a base charge made of highly explosive material such as pentaerythritol tetranitrate or lead azide. The ignition cables, which protrude from the cartridge, are located in the upper part of the cartridge. A voltage applied to the ignition leads leads to an abrupt breakout of the initiator. To date, this abrupt outbreak has produced 1 ² R heating of a bridgewire that has been directly associated with a sensitive explosive, sometimes referred to as a "detonator" explosive. When this explosive or explosive is initiated, the pentaerythritol tetranitrate (PETN) and / or the lead azide of the base charge detonates. This detonation then initiates the primer charge in which the detonator is installed, so that the less expensive, loose explosive material of the individual charges, which are distributed over the field to be detonated, is then subsequently initiated.

To achieve a delay, a delay explosive is placed between the detonator explosive and the base charge. This intermediate charge controls exactly the time between the abrupt burst of the ignition device and the explosion of the highly explosive base charge.

Such electrical detonators are used by millions around the world to lay out explosive fields for earthmoving in the desired, controlled manner. Since the initiation of the detonators via a bridging wire is done by 1 ² R heating, a low voltage signal can be used. This makes the detonators vulnerable to electronic count measurements (ECM), radio frequency interference (RFI), electromagnetic interference (EMI) and electromagnetic impulses (EMP). Because low voltages can initiate these detonators, stray electrical energy, such as lightning and electrical equipment, can induce a detonation voltage on the detonator wires. So far, this has prevented the detonators from being detonated a long time before detonation.

Since detonators used to contain highly explosive materials, they were classified in such a way that their mode of transport was restricted. In addition, the previous electrical detonators were somewhat sensitive to shock detonation. Also, due to their sensitivity to electromagnetic pulses that could induce a detonation voltage, these existing detonators were not necessarily rock hard. In addition, older detonators were sometimes not insensitive to radar signals. All of these limitations on the use of standard electrical detonators have been known for some time and must be considered in the handling, transportation, and use of these detonators around the world. There was therefore an urgent need for an electrically detonated detonator that is insensitive to the many existing electrical and magnetic fields and the vicissitudes that occur in handling in the explosives industry. For this reason, many situations have led to electrical detonators being dispensed with in favor of non-electrical systems. This reduces the control and effectiveness of blasting and has been a significant factor in limiting the success of detonators.

Many years ago, an explosive device known as a "slapper" had been proposed that used a flat aluminum sheet to propel another plastic film called a "flyer". However, this theoretical concept was not used for electrically detonated detonators and was also not used in the art of blasting.

The object of the invention is to provide an improved electrical detonator or an ignition system for an electrical detonator, which is insensitive to environmental influences, in particular magnetic and electrical fields and not sensitive to shock, and which can be safely transported and used in all normal environmental conditions and which can be produced cheaply and is easy to use.

This object is achieved with the invention solved an electrically ignitable detonator or detonator, which contains a basic charge made of highly explosive material, such as lead azide or pentaerythritol tetranitrate (PETN) and an initiator that generates an abrupt outbreak when a selected voltage is applied, which detonates the highly explosive basic charge. In the case of an electrically ignitable detonator of this type, the invention consists in an improvement in the area of the initiator or the primer. According to the invention, the ignition means has a contact surface (junction) made of energetic material. This is understood to mean a material that generates an electric arc when it is subjected to a high voltage pulse that has a considerable dwell time due to a capacitor discharge. The electrical energy of the arc is retained because the arc is retained in the enclosure of the housing or the container.

According to a preferred embodiment of the invention, the energetic material is a pn junction (PN junction) or a chip with a light-emitting diode (LED chip) in a standard epoxy resin or glass housing of the type such as that manufactured by Panasonic under the Designation P380 (LN264CP) is sold. Other LED chips that have pn junctions are described, for example, in U.S. Patent Nos. 4,412,234, 4,447,825, and 4,920,404. A package for an LED chip is described in U.S. Patent 4,907,044.

There are other energetic materials, metals, and semiconductors in which a high voltage capacitive electrical pulse in the contact or transition surface creates an arc that can be held closed until it is closed by a seal such as that found in the clear epoxy - Or glass housing of a standard LED device is present, is converted into a plasma. The ignition means includes the area made of energetic material as defined above. This contact surface is encapsulated in a plastic or glass cover housing, for example in a standard epoxy housing which surrounds the LED chip in a standard LED device.

According to a further feature of the invention, the end housing surrounding the contact area made of energetic material is provided with a direction-controlling dividing means which faces a selected direction and is at an effective distance from the contact area which is considerably smaller than the remaining thickness of the dividing means, which is the contact area surrounds. In this way, an area of the plastic or glass end housing has a reduced thickness. Therefore, if a voltage pulse that has a high initial voltage and is held by capacitance is passed over the contact area, this contact area is converted into an electric arc. This arc remains trapped until it is converted to plasma by a limited, exothermic reaction at high temperature and pressure.

According to the invention, the voltage pulse is generated by an ignition machine, which is actuated by a controllable silicon rectifier SCR for voltages up to more than 1000 volts and with a trigger for circuits with higher voltages.

The pulse has a voltage above 500 volts. It is held for a while by capacitance. This arc hold time is generally less than about 10 to 30 microseconds. The voltage pulse immediately changes to the high initial voltage and is then held by the capacity of the machine for at least 5 to 10 us before the voltage drops to approximately 50% of its initial value. This maintains the electric arc energy generated by the initial current that the high initial voltage of the voltage pulse has caused to flow to hold the arc, as is the case with an electric arc welding machine. Since this arc is enclosed by the hard plastic or glass housing, the temperature inside the electric arc rises. An exothermic reaction also increases the pressure, so that a plasma is formed which finally tears the direction-controlling distribution means.

To ensure this tearing action, the effective spacing or thickness of the partitioning agent on the contact surface is thick enough to complete the exothermic reaction until the plasma forms and thin enough to allow the plasma to break through on the controlled partitioning surface or partition. The plasma, which is formed by the electrical arc energy which is maintained under lock and key, penetrates through the partition wall a predetermined distance far in the selected direction, which is determined by the directional specification of the controlled partition wall. This plasma column is driven through the end wall, using a shaped charge phenomenon and producing a column of high impact, high temperature and high energy which results from the sustained exothermic reaction on the energetic metal compound.

It is particularly expedient if the base charge is fastened in the detonators in the aforementioned selected direction and is arranged at a distance from the torn partition wall that is smaller than the predetermined distance that that from the exothermic reaction driven plasma goes through. As a result, the vaporized gases and / or vaporized metals, which come from the arc energy surface with high impact, high energy and high pressure inside the column, hit the highly explosive base charge and detonate either the lead azide or the PETN. Lead azide is relatively sensitive and is arranged at a predetermined distance, so that it is immediately impacted and detonated by the plasma column coming from the partition. Lead azide is sensitive to shock. PETN is a less sensitive, highly explosive explosive. If only PETN is used, a longer voltage pulse can be used to maintain the electric arc for a longer period of time so that the pressure in the space or cavity increases to the extent that an increase in temperature and pressure results. The detonation of the relatively less sensitive PETN is achieved by pressure and heat as well as by nano- and micro-speed impact of the plasma column, ie by high-speed impact on the PETN.

According to the invention, the pn junction is activated by a voltage pulse of high energy, which generates an electrical arc and maintains this electrical arc by supplying electrical energy from the igniter into the arc. The arc or plasma is held by continuous infusion of high energy, keeping the voltage high and the capacity relatively high. This energy maintenance technique can be carried out with a blasting machine that provides approximately 1 to 4 kV. Such a machine maintains approximately 50% of the initial arc voltage for 5 - 10 /1.S. The capacitance rises to 10-20 uF so that the plasma created by the sustained voltage pulse emits high speed surge energy when the plasma reaches the spaced base charge of the electrical detonator. In this way, the invention anticipates an uninterrupted plasma. A partition or other means is also provided to focus or direct the plasma. This can be achieved by a standard electrode in an LED housing, by a back plate added to the housing and / or by a shaped cavity in the direction-controlling partition. Here, the shaped cavity may have a desired shape such that it allows the stream of material of a well-known shaped charge to flow through the partition toward the base charge.

When using the invention, the basic charge can be a standard shock tube, PETN, lead azide or the like. be. In another embodiment of the invention, the base charge can also be covered with a metal partition, for example a layer of copper, through which the plasma column penetrates in order to detonate the base charge. Two separate and different security barriers are then provided. The first or primary barrier is the capsule housing. This housing cannot tear before the plasma is formed. The plasma cannot arise without the use of a voltage pulse that has a high initial voltage that is maintained for an extended period of time. The plasma is generated by continuously supplying electrical energy to the initially generated arc such that the electrical arc energy in the sealed housing initiates the build-up of pressure and temperature until a plasma is formed. After the formation of the plasma, the partition of reduced size is immediately torn, so that the plasma emerges in a straight line and in a preselected direction, which is controlled by the formation and orientation of the partition. Here, the partition directs the plasma against the second safety partition that covers the explosive base charge. These two barriers cannot be destroyed by the electrodes of the detonator being exposed to stray electromagnetic fields or signals.

In another embodiment of the invention, the standard LED device, which contains the pn junction or the embedded chip and is encapsulated in clear epoxy or glass, is modified by grinding the surface of the device until between the contact surface and the The area initially lying on the LED housing has a thickness of 1/32 "to 3/32". This thin wall defines the tear point of the end housing. In practice, this distance is approximately 1/16 ".

Such LED devices have a substantially concave anode surface that carries the chip of energetic material that generates the emitted light. A gold wire is used as the cathode. This gold wire conducts the electrical voltage pulse to initiate the electric arc when a voltage pulse, as proposed by the invention, is supplied to the LED housing. The gold evaporates when the interface creates the arc. Energy continuously supplied to the electric arc generates not only a plasma gas, but also a plasma that contains vaporized gold. As gold vaporizes, it is known to expand approximately 30,000 times. This gold vapor increases together with the gas plasma that is contained in a sealed Area maintained arc is generated, the impact and energy level of the plasma when it hits the second safety barrier over the base charge. If the partition on the LED housing is smaller than about 1/32 ", the plasma cannot be generated by the arc, since a cooling effect or gas migration can then take place there through the thin partition. It has been found that the the direction-controlling partition, which is generated by grinding the surface or top of the LED housing, must have such a thickness that it ensures the termination of the electric arc until the energy in the closed arc generates a plasma, which is then by the intentionally reduced area of the LED housing breaks out.

It is understood that a standard bridge wire is used with a backplate that is embedded in clear, hard plastic or glass and has the reduced bulkhead that is provided on the bridge wire. The wire must be made of energetic material so that it first creates an electric arc and then a plasma while maintaining the arc for 5-30 us. The back plate is a force counteracting plate, such as the anode of a standard LED device. The backplate ensures that the plasma forms in the transition layer in order to break out through the partition and towards the highly explosive basic charge in the electrical detonator.

According to the invention, the electric arc must be completed to generate the plasma, while the arc energy inside the glass-like capsule housing rises continuously. The resulting plasma breaks through the housing partition and causes the basic charge to detonate. The lead azide could, of course, either have a copper layer on the top or be encapsulated in some way to prevent detonation, except for detonation by the plasma which is driven through the second barrier across the base charge.

In another embodiment of the invention, the energetic material could also be a metal, for example certain metals, which are used as a bridging wire for generating an electric arc, which is then converted into the plasma in a glass or hard plastic housing. The plasma tears the housing and finally detonates the detonator.

The first initiator system of the invention is the formation of a plasma, whereby an electric arc is first generated and the electric arc is supplied with electrical energy while the arc is kept in a closed space, so that the energy supplied to the electric arc is not by radiation, conduction or convection escapes. Formation of the electric arc inside a sealed plastic or glass case prevents heat loss and allows the heat, pressure and energy of the arc to build up inside the sealed chamber or case until it breaks out of the case. Here, the housing is designed so that the eruption takes place in a previously selected direction and gives the plasma a direction. This alignment is improved by a recess in the housing partition that is adapted to the load. This partition, through which the eruption occurs, is thin; however, it has a concave shape in order to achieve the effect of a shaped charge or the monro-like effect.

The encapsulated material, i.e. the epoxy, or glass, adheres directly to both the pn junction or chip and the lead wires of the LED device so that the exothermic reaction takes place within a highly insulated, controlled chamber. This confinement and the provision of a directional partition creates the directional plasma.

The highly explosive base charge is located at a distance from the partition. This distance is so large that the beam generated by the plasma with the shaped charge effect has a high impact energy when it strikes the basic charge arranged at a distance. If, for example, a lining is enclosed in this plasma metal, the fluid is not viscous. As a result, the impact properties of the plasma are increased when it strikes the basic charge arranged with a gap. This volume space through which the plasma passes is a second reaction chamber. This hollow chamber causes a diesel effect and allows an increase in pressure so that the gas in the intermediate chamber reaches an increased pressure. This pressure affects the highly explosive base charge. As stated above, this second inter-chamber reaction allows the use of a less sensitive, highly explosive explosive for the base charge in the detonator.

In order to ensure that the beam or plasma flows from the arc energy range in a precisely defined direction, the partition wall can have a break point, for example an etched line. As a result, the high energy plasma, which is focused by the Monroe effect, by a focusing device or by both, is aligned in a straight line and focused, which intersects the highly explosive base charge.

Although the invention has so far been described with a standard LED housing, it can also use a linear LED, for example a Panasonic P389 (LN2G). This type of LED device also has a pn junction between two linear electrodes. When the plasma is generated according to the invention, it is directed radially outwards by the linear LED device. To control or focus the high-energy plasma, part of the peripheral wall surrounding the LED is reduced in thickness. As a result, the plasma passes directly through this part of the housing material, which can be aimed in any direction in order to detonate a highly explosive explosive arranged at a distance. The detonation of the highly explosive explosive is primarily based on impact and is not necessarily a temperature reaction. The reaction that occurs in the gap between the initiator and the base charge has a greater effect because the time is longer and the energy conducted into the electric arc is greater. This second detonation may become more important if multiple initiators direct individual plasma columns into a chamber that is located above the explosive base charge. Since all plasma columns are directed into this compartment or chamber, the temperature and the pressure in this chamber increase so drastically that the actual explosion of the base charge can be increased by the second detonation.

The shape of the voltage pulse can be changed to control the arc and the plasma generated by the exothermic reaction. When using a high initial voltage and a low holding capacity, the pulse causes the energy from the capacitors in the detonators to drop rapidly. This creates a sudden burst of arc energy in the confined area. This effect is an abrupt voltage pulse. A higher capacitive reactance in the ignition machine extends the length of the high voltage part of the voltage pulse. A reduced initial voltage reduces the amount of initial energy that the electric arc can form. As a result, the starting voltage and the magnitude of the voltage maintaining capacity in the igniter are chosen so that the initiation of the electric arc and the length of time during which energy is supplied to the arc to form the plasma can be controlled. The temperature, pressure, kinetic energy and other factors in the closed area are affected by the initial voltage and the length of time that the current is supplied by the voltage pulse. The initial voltage must be sufficient to create an arc in the energetic material. It has been found that at least about 600 V and preferably in the range of 1-4 kV are necessary for this. The capacitance should be large enough to keep the voltage above 50% for at least 10-20 us. In this way, the arc is formed and held for a longer period of time which is sufficient to allow a plasma to form within the closed area.

The electrical parameters of the electrical voltage pulse used in the formation of the exothermic reaction to convert the electrical arc energy into a plasma for breakout through the closed housing are controlled to produce the energy for the desired number of detonators to be detonated. The capacitance is preferably generally in the range of less than 0.1 uF to a preferred range of 10-20 uF. This voltage pulse maintains the plasma even after the partition breakthrough has occurred.

As the initial voltage of the pulse rises, the duration of the pulse becomes shorter provided the capacitance remains the same. As the capacity increases, the duration of the pulse also increases. In this way the parameters of the electrical voltage pulse are controlled in order to precisely determine the property of the plasma; however, the invention only relates to the formation of the plasma which breaks out through the closed housing and acts on the highly explosive base charge of a detonator cap. The high energy builds up a pressure that escapes through the housing when the exothermic process takes place. The inclusion of the arc is therefore essential for the formation of the necessarily directed plasma.

Various energetic materials can be used, such as the typical 111, V group compounds. Aluminum gallium arsenide is common. Gallium arsenide is often used for a pn junction and is the preferred energetic material of the invention. The exothermic reaction of the energetic material creates a chemical transformation that releases thermal energy in the sealed housing. This creates the electric arc explosion by the formation of a plastic plasma by introducing energy into the electric arc. The plasma is mechanically focused or directed. By using metal vapors, such as gold, in a connecting wire of a standard LED device, metal vapor is trapped and helps Charge effect of the exploding plasma. The plasma has considerable velocity, high heat content and extremely high kinetic energy when it enters the space or cavity above the base charge of the detonator. The focusing of this plasma either through the shaped charge effect or through a lens, concentrates the energy of the plasma on the highly explosive base charge.

A low standard voltage pulse on the contact surface of the energetic material would only result in melting with low energy, which does not break the enclosing chamber. The pn junction would only burn out and high energy would not be generated in the sealed housing which would create an electrical arc and then maintain an arc to form a plasma which would then break out into a space or cavity. For this reason, the pn junction according to the invention is overexcited to detonate under the action of the accumulated arc energy. This electrical arc energy is held inside the closed housing to increase its temperature and pressure. The plasma is then directed onto and / or focused on the second barrier above the base charge. The electric arc initially exceeds 6000 / C and has higher temperatures while being trapped before the plasma was formed.

The invention has the advantage that the initiator causes the detonator to be detonated, but is not activated by stray fields, shock or other influences that normally occur when handling the detonator. Another advantage is that the initiator according to the invention has two safety barriers, one of which surrounds the initiator and the other of which covers the basic charge arranged at a distance from the initiator.

The initiator for an electrical detonator can be manufactured relatively inexpensively, is reliable in use and cannot lead to unintended detonations.

• Fig. 1 eine Sprengkapsel nach der Erfindung im Längsschnitt,
• Fig. 2 den Initiator der Sprengkapsel nach Fig. 1 in einer vergrößerten Teildarstellung,
• Fig. 3 eine andere Ausführungsform der Erfindung, die die wesentlichen Teile des Initiators und der Sprengkapsel in einer auseinandergezogenen, schematischen Darstellung entsprechend Fig. 2 zeigt,
• Fig. 4 bis 6 andere Ausführungsformen der Erfindung in der Fig. 2 entsprechenden schematischen Teilschnitten,
• Fig. 7 eine elektrische Sprengkapsel nach der Erfindung, bei der für die Grundladung ein Stoßrohr verwendet ist, in einem Längsschnitt,
• Fig. 8 einen Initiator mit Brückendraht im Teillängsschnitt in vergrößerter Darstellung,
• Fig. 9 den Gegenstand der Fig. 8 in einem Querschnitt nach Linie 9-9,
• Fig. 10 einen Initiator mit einem Schmelzdraht aus energetischem Metall, der den Übergang bildet, in einem Längsschnitt in vergrößertem Maßstab,
• Fig. 11 eine elektrische Sprengkapsel mit einem Initiator nach der Erfindung, der aus einer Lithium/Jod-Batterie besteht, im Längsschnitt,
• Fig. 12 eine andere Ausführungsform einer Sprengkapsel nach der Erfindung, die drei Initiatoren für die Detonation einer einzelnen Basisladung aufweist, im Längsschnitt,
• Fig. 13 einen schematischen Grundriß, der den Gebrauch von vier separaten und verschiedenen Initiatoren für die Detonation einer einzelnen Sprengladung zeigt,
• Fig. 14 die Seitenansicht und teilweise den Längsschnitt einer Radial-LED-Vorrichtung, wie sie in einem in den Fig. 15 und 16 dargestellten Explosionsnetzwerk verwendet wird,
• Fig. 15 eine andere Ausführungsform der Erfindung in einer perspektivischen Darstellung, bei der eine Basisladung von mehreren Radial-LED-Vorrichtungen umgeben ist, die als Zünder dienen,
• Fig. 16 den Gegenstand der Fig. 15 in einer Stirnansicht,
• Fig. 17 ein Elektrodiagramm, das das Verfahren zum Zünden einer Reihe von Sprengkapseln zeigt, welche die bevorzugte Ausführungsform nach der Erfindung verwenden,
• Fig. 18 ein Diagramm des bei der bevorzugten Ausführungsform nach der Erfindung verwendeten elektrischen Impulses und
• Fig. 18A und 18B Diagramme, die die elektrischen Eigenschaften der Impulse zeigen, wie sie nach der Erfindung verwendet werden.

Further features and advantages of the invention result from the following description and the drawings, in which preferred embodiments of the invention are explained in more detail using examples. It shows:

• 1 is a detonator according to the invention in longitudinal section,
• 2 shows the initiator of the detonator capsule according to FIG. 1 in an enlarged partial view,
• 3 shows another embodiment of the invention, which shows the essential parts of the initiator and the detonator in an exploded, schematic representation corresponding to FIG. 2,
• 4 to 6 other embodiments of the invention in Fig. 2 corresponding schematic partial sections,
• 7 shows an electrical detonator according to the invention, in which a shock tube is used for the basic charge, in a longitudinal section,
• 8 an initiator with bridge wire in partial longitudinal section in an enlarged view,
• 9 is the subject of FIG. 8 in a cross section along line 9-9,
• 10 shows an initiator with a fuse wire made of energetic metal, which forms the transition, in a longitudinal section on an enlarged scale,
• 11 shows an electrical detonator with an initiator according to the invention, which consists of a lithium / iodine battery, in longitudinal section,
• 12 shows another embodiment of a detonator according to the invention, which has three initiators for the detonation of a single base charge, in longitudinal section,
• 13 is a schematic plan view showing the use of four separate and different initiators for detonating a single explosive charge;
• 14 shows the side view and partly the longitudinal section of a radial LED device, as is used in an explosion network shown in FIGS. 15 and 16,
• 15 shows another embodiment of the invention in a perspective view, in which a base charge is surrounded by a plurality of radial LED devices which serve as igniters,
• 16 shows the subject of FIG. 15 in an end view,
• 17 is an electrical diagram showing the method of igniting a series of detonators using the preferred embodiment of the invention.
• 18 is a diagram of the electrical pulse and used in the preferred embodiment of the invention
• Figures 18A and 18B are diagrams showing the electrical properties of the pulses used in the invention.

1 and 2, an explosive device 10 is shown which has a tubular, drawn metal cartridge or sleeve 12, in the lower part of which a basic charge 14 is arranged. The basic charge consists of two components, namely lead azide 14a in the upper part and PETN (pentaerythritol tetranitrate) 14b in the lower part. The basic charge is defined as the charge that receives the initiation and detonates an ignition charge or another explosive that is associated with the detonator capsule 10. The lead azide is sensitive to spray, while PETN is more sensitive to pressure and heat. An inner cap or a barrier wall 16 made of copper above the lead azide 14a of the basic charge 14 is provided as a second safety barrier. The lead azide could also be encapsulated with metal or another material that then forms the second barrier 16.

The barrier wall 16 has a distance b from the lower end of the initiator 20, which is designed according to the invention. In the preferred embodiment, a Panasonic P380 (LN 264CP) LED device is modified so that it can be used for the invention. The initiator has detonator lead wires 22, 24 through which a voltage signal or pulse is applied to initiate an abrupt burst of initiator 20 which detonates detonator 10. The distance b defines an intermediate space or cavity 30, which represents a second initiation chamber.

The pressure of the gas, and thereby its temperature, increases in the cavity to help detonate the base charge 14. A suitable rebate seal 32 is arranged around the neck of the cartridge 12.

The Panasonic LED device has a pn junction 40 which is made of energetic material such as gallium arsenide or aluminum gallium arsenide and which has been selected to provide the ignition system according to the invention. The connection 40, which is formed by the LED chip or the pn junction, is supported in the interior of a concave anode 42, which has the function of a lens and focuses the plasma subsequently formed in the direction x. This anode forms a pressure-resistant or resistant protective plate or back plate for the initiator 20.

The cathode 44 is a fine gold conductor connected to the igniter lead wire 24, which is connected to an electrode or a side terminal of the pn junction or chip 40. The other electrode or side clamp of the connecting element lies against the concave inner surface of the anode 42. This entirety of pn junction 40, anode 42 and cathode 44 is encapsulated in clear epoxy resin or glass 50 and forms a closed capsule housing for initiator 20. The housing is the body of the LED device used in the preferred embodiment of the invention.

A directional separating means 52 is formed by a flat partition, the outer surface of which has a distance a from the chip 40 which is chosen to be thick enough to limit an electric arc at the junction 40, while this electric arc from the conductors 22nd and 24 receives energy until the arc energy is built up sufficiently that it can form a plasma P. However, this distance a is also thin enough to allow the plasma to tear the partition 52 and to flow the plasma in the selected direction x against the barrier wall 16 of the base charge 14, as best shown in FIG. 2.

The partition wall 52 has a recess which acts as a lens and concentrates the plasma jet P. The back plate 42 can help focus and align. These features control the direction of the plasma jet P so that it coincides with the selected direction x.

The shape of the partition 52 is produced by grinding out the upper part 60 of the Panasonic LED housing unit. In practice, this upper part 60 is removed by milling or grinding to produce a partition 52 with a thickness of 1/32 "- 3/32". Preferably the thickness is about 1/16 ", but the thickness should be above about 1/32". Using this thickness, the wall strength and integrity of the bulkhead 52 is sufficient to protect against deterrence or loss of the thermal energy generated at the junction 40 when a high voltage pulse is applied across the conductors 22, 24 to create an electric arc. While the pulse persists and leads energy into the arc, the arc is confined until the energy in the electric arc and in the space surrounding it is sufficient to form a plasma. The transfer into the plasma P results in an immediate and abrupt explosion through the partition 52. Here, the plasma P enters the cavity 30 and impinges on the barrier wall 16 of the base charge 14.

In order to support this abrupt breakthrough of the partition 52, an etched line 62 is drawn over the flat circular surface of the partition 52. In order to achieve the effect of a shaped charge, the partition 52 is surrounded by a conical peripheral wall 54. This will gives the plasma a direction. In this way, the plasma P is directed as a shaped charge jet into the chamber or cavity 30 and against the base charge. The distance between the partition 52 and the barrier wall 16 or the charge 14 can be changed depending on the type of initiator 20 used.

The polarity can be reversed. As shown, the pn junction will initially initiate the plasma flow, the initial energy and the flow rate. This is followed by a rupture of the gold wire, whereby vaporized gold is fed to the plasma. Gold is a heavy metal that adds a greater impact than a lighter metal such as aluminum.

As best seen in Fig. 17, a high voltage pulse F is applied via conductors 22 and 24 when the detonator is to detonate. The high voltage immediately creates an electrical arc at connection 40. This arc is maintained in that the voltage present at the junction is maintained by the capacitance coming from the circuit of a capacitor discharge igniter. This high voltage is maintained at a level of at least 50% of the initial voltage for at least about 10 µs. The capacity is large enough to maintain this high voltage. High voltage naturally results in a high current flow, which supplies energy to the electric arc at the junction 40. This energy builds up pressure and temperature in the interior of the sealed housing 50 in an exothermic reaction. This exothermic reaction of the held arc increases the arc energy until a plasma is formed. This plasma drastically increases the pressure and temperature at the connection 40, so that the gold conductor 44 evaporates and the partition 52 is torn, which thereby allows the plasma P to fire directly through the cavity 30 into the base charge 14.

The impact detonates the base charge. If an insensitive, high explosive, possibly PETN, is present, the diesel action in cavity 30 leads to an immediate, drastic temperature rise, while the pressure and temperature of this cavity increase. This leads to a second detonation for less sensitive, highly explosive explosives. In this case, the pulse F can be extended to supply energy to the plasma P for the second firing or detonation. In practice, the first detonation system is a creation of the plasma P. The second reaction is the diesel effect in the section or cavity 30. As can be seen, only a precisely controlled pulse F held at a high voltage via the lines 22 and 24 can detonate the initiator 20. This requires a safety barrier on the sealed housing 50 and on the copper layer or on the barrier wall.

3 shows a modification of the preferred embodiment. The conductor 22 is connected to an anode 100, to which a doped carrier, such as a pn layer made of energetic material, is applied. The connection is the same as that used in an LED chip. However, the transition layer 102 has a conical shape to act as a shaped charge. This formation itself creates a Monroe effect on the transition surface. The cathode 104 is a gold conductor as described above. When a high voltage pulse F is applied via connection 102 and an arc forms, the gold evaporates. All of these elements (100, 103, 104) are encapsulated in a clear plastic or glass in the preferred form of a crystal-clear, hard epoxy resin as the housing 50. The partition 52 is coated with a metal insert 110 in order to achieve an armor effect which is to be used in the case of the shaped charge effect. This insert provides metal to increase the speed and impact energy of the plasma P when it breaks out under the arc energy created at the junction 102. Here, too, an etched line 112 precisely controls the breaking point of the thin partition wall 52, the arrangement and orientation of which indicates the selected direction in which the plasma subsequently produced flows against the barrier wall 16 and the base charge 14.

This particular embodiment of the invention shows a wider transition surface 102 that contains more material than the chip 40 in the preferred embodiment of the invention. The formation of the contact area 102 as a shaped charge area also increases the energy of the plasma stream. The shape of the transition surface 102 is conical. As a result, the plasma P is directed along the axis x. The insert or liner 110 serves to additionally provide vaporized metal for the plasma stream, which is generated by the shaped charge. This additional metal is evaporated together with the gold wire or cathode 104 to create a non-viscous fluid stream.

4 through 6 serve to explain two separate concepts for the directional control of the plasma P that is formed after the combined arc energy has caused a significant increase in temperature and pressure. The housing enclosure 50 prevents the heat from escaping or the ingress of contaminants, so that the arc can pass into a plasma. In Fig. 4 the rich Forming partition a flat bottom surface 120, which is ground from the tip of a standard LED unit to reduce the thickness or distance of the surface 120 from the pn junction surface 40. If the continuous exothermic reaction of the electric arc increases pressure and temperature and the plasma P forms, it breaks through at the point of least resistance. This is the case perpendicular to the wall or bottom surface 120. The wall itself is directional by nature.

If a conical peripheral surface 54 is provided around the partition 52, as shown in FIG. 5, the flat lower surface of the partition is circular and causes the plasma to move in the direction x. This movement is refined with parallel alignment and concentrated by the peripheral wall 54, which creates a shaped charge surface. 4, the plasma P is focused by the concave shape of the anode 40. 5, the parallel alignment takes place with concentration of the plasma column by the shape of the recess 130, which is formed by the partition wall 52 and its circumference 54. In both cases, the plasma column is focused and concentrated along the selected direction or axis x.

In the preferred embodiment of the invention shown in FIG. 6, both the focusing action of the rear, concave anode 40 and the shaped recess 130 are provided. As a result, the energy is concentrated in a narrow plasma column, which flows directly along the axis x and concentrates the energy and impact energy in this narrow column. Of course, either the focusing action or the shaped charge formation can be used in the invention. The preferred embodiment shown in Fig. 1 uses both concentration concepts.

In another embodiment of the invention, shown in FIG. 7, the base charge 14 is in the form of a shock wave tube 150 to detonate a high explosive charge at the opposite end of the tube. A shock wave or detonation wave runs through the pipe to the explosive. This tube has an upper end 152 cut at an angle to give initiator 20 greater access. The inner passageway 154 may be provided with a high explosive liner 156, as is common in practice, so that the blast wave may pass through the tube or cause a progressive explosion along the inner surface of the passageway 154. The intermediate space 160 receives the plasma coming from the initiator 20, which flows along the axis x, which coincides with the central axis of the through opening 154 of the shock wave tube 150. Spacer material 162 holds the shock tube 150 in place so that the plasma emanating from the partition 152 can pass through the shock tube. The spacer material 162 is inert and allows the tube to expand. The plasma initiates the action of the shock wave through the tube. The activation of the shock wave tube is equivalent to the detonation of the base charge 14. The shock wave tube is identified as basic charge 14c.

It is possible to provide a junction area enclosed by a metal wire that differs from the pn junction of an LED chip, as long as this wire can generate an electric arc that can be held in a closed area by a high voltage applied to the Conductors of the initiator as long as it is necessary for the build-up of pressure and temperature in the delimited space to generate a plasma. The wire must form the arc and enable the leads to supply energy to the arc until the plasma forms. After the formation of the plasma, the thin wall in the sealed housing can no longer withstand the pressure built up by the arc energy. The partition then tears in the controlled direction x to initiate the base charge. This modified implementation of the invention is illustrated in FIGS. 8 and 9, where the initiator 200 has a capsule housing made of hard plastic or glass 202 in order to enclose a connection in the form of a bridge wire 204 which contains energetic metal. The bridging wire creates an arc between lead ends 206 and 208 and allows that arc to collect energy to increase the temperature and pressure in the capsule housing until that temperature and pressure are high enough to generate a plasma. This plasma cannot, of course, be generated by the arc if a quenching effect is generated from outside the housing 202 or material flows into the arc region through the housing. Protective or backing plate 210 is a pressure-resistant plate that propels the plasma through the breakout location, providing an indentation or recess 212 with a circular, flat inner surface 214 and a conical outer peripheral wall 216, as described above.

The preferred embodiment of the invention uses the pn junction of a standard LED device. A bridging wire of energetic material that is sufficiently ionized when an arc is formed can perform the function of the invention, which is that the arc energy is used to form a plasma in a confined space where when the plasma breaks out through the directional wall and hits the base charge in the detonator.

FIG. 10 shows a similar modification of the invention, in which the initiator 220 has a sealed housing 222 and connecting leads 224 and 226. An igniter 230 made of energetic metal is arranged between the connection conductors and generates an electric arc inside the sealed housing, to which energy is supplied by the high-voltage energy pulse until the pressure and the temperature in the sealed housing are sufficiently high to generate a plasma generate, which breaks through the recess 232, which has a flat lower surface 234 and a conical side wall 236.

In the embodiment according to FIG. 11, the detonator capsule 10 "has parts which are similar to those of the detonator capsule according to FIG. 1 and which are provided with the same reference numerals in this respect. In this particular embodiment, the initiator 300 consists of a standard lithium / iodine Battery in which the reactive energetic material consists of a lithium layer 302 and an iodine layer 304. This material interacts with the conductors 22 and 24 to form an arc on the lithium layer 302. This arc is maintained by the housing 12 until a plasma forms and is directed against the barrier wall 16. For the alignment of the plasma, a shaped charge concept is used, for which a hemispherical recess 310 is provided, this recess being covered by a glass layer 312, around the arc in the cartridge 12 above the recess 310 The recess guides the plasma through the cavity 30, in which a pressure builds up, which d The ignition of the basic charge is supported.

FIG. 12 shows a large electrical detonator D in which the base charge 14d is ignited simultaneously by three separate initiators 20, which direct their individual plasma discharges along the axes x to the concentration point y. The energy at this point ignites the base charge, as described above.

FIG. 13 is a similar schematic illustration in which the detonator E has a single base charge 14e surrounded by four separate initiators 20. The plasmas generated by these initiators are directed along their individually selected directions or axes x so that they strike the base charge 14e. It can be seen that two or more initiators can be used in a detonator to intensify the amount of energy available for the detonation of the base charge. This is quite important in view of the fact that the standard LED units are relatively small in size for the purposes of practicing the invention and produce only a limited Joules of energy. It is believed that the abrupt initiation and tearing of commercially available LEDs that have been modified to practice the present invention produce approximately 20 millijoules.

As described above, a radial LED such as Panasonic P380 (LN2G) could also be used in the practice of the invention. This is shown schematically in FIGS. 14 to 16, in which a standard LED 400 is provided. Part of the cylindrical surface that emits light is ground. This area is designated 402. The surface could be ground all around, so that the plasma is directed radially outwards in all directions. In the illustrated embodiment, however, only a portion of the cylindrical surface is ground to create a limited thin area for the breakthrough. This breakthrough area gives the direction of the plasma directed outward from the other pn junction of the linear or radial LED unit 400. The selected, ground part 402 is on the side of the epoxy tube 404. Line wires 410, 412 are connected to an internal pn junction, as described above.

Using this alternative concept of the invention, a base charge 14f may be surrounded by a plurality of initiators 400, the selectively ground surfaces 402 of which, as indicated by the arrows in FIG. 16, are directed radially inwards. These initiators are housed inside an outer metal container 420, which forms an annular space 422 with the inner base charge 14f, which surrounds the inner base charge 14f.

When the initiators 400 detonate, the plasma of each initiator 400 is directed directly against the base charge. The plasma is also directed into the annulus 422. Pressure and temperature rise in this chamber and cause the base charge to ignite in connection with the direct exposure to the plasmas coming from the individual detonators.

In FIG. 17, BM denotes an ignition machine which has an ignition voltage of 1-4 kV and an internal capacitance of 20-20 uF. With 1000 V one can detonate seven detonators 10 with 10 foot lines between the detonators. The voltage pulse F generated by the ignition machine BM is shown schematically in FIG. 18. The impulse creates a rapid The voltage rises and falls gradually. In the illustrated embodiment, as used in the present invention, the pulse F has an initial or ignition voltage that increases to approximately 2000 V within approximately 1.0 µs. This voltage then remains at a relatively high value due to the capacitance in the ignition machine BM, so that the voltage after 10.0 µs is still approximately 50% of the initial value. This initiates a significant amount of electricity to generate energy in the arc. The arc is formed immediately after the 2000 V is applied to the leads 22 and 24 of the initiator 20.

18A shows a pulse F1 with an initial voltage of 2000 V. The pulse F1 is held at 10 µF. In this example, the voltage remains fairly high, but the degree of discharge is greater than that shown in Fig. 18A because the initial voltage is 2000V.

The pulse F2 in Fig. 18B has an initial voltage of 600 V. In this example, an igniter with approximately 100 µF is used. It can be seen that the pulse F2 keeps the voltage for a longer period due to the high capacity of the igniter.

Both pulses F1 and F2 pump a considerable amount of energy into the arc that forms at the junction of the initiator. The preferred embodiment of the invention uses a pulse similar to pulse F1. This pulse is shown as pulse F in FIG. 18.

The initial voltage of the pulse F, F1 or F2 is combined with the capacitance and delivers the high energy under the voltage curve of the pulse. At voltages above 1000 V, the capacitance is in the order of 10 - 30 µF. This creates a fast plasma with a high impact energy. If the voltage is lower, for example 500-700 V, the capacitance is increased to a value of 50-150 µF, which creates a slower-acting plasma.

Two different energy supply groups were used to test the ignition machines. One used a controllable silicon rectifier (SCR) as switching means and a capacitor charge up to 1000 V. The second supply circuit is the DuPont igniter SS1100, which uses a trigger tube as switching means and has a fixed capacitor charge capacity of 2000 V. Dispensing of the initiators 20 was several times faster with the trigger tube circuit. The tests were carried out without inductance or in series with the SCR-connected resistor - only with the resistor normally present in the layout of the circuit.

The results of the experiment were such that 600 V and 30 µF detonated an initiator 20 with a lead up to 600 feet. A pulse of 2000 V and 12 µF detonated 10 glass initiators with a lead up to 30 feet. A pulse of 2000 V and 12 µF detonated 3 plastic initiators 20 with a lead up to 150 feet. The energy had to be supplied to the initiator very quickly, within less than about 1.0 µs. The preferred blasting machine is the trigger tube unit. A very fast SCR machine can be used if dv / dt is large enough to deliver the maximum voltage in less than 1.0 µs.

Claims (32)

1. Electrical detonator, in particular for detonators, with a base charge (14) made of highly explosive material, an ignition means (20) for generating an abrupt eruption when a selected voltage is applied to the ignition means (20) and with means for detonating the base charge (14) when the abrupt eruption of the ignition means (20) takes place, characterized in that the ignition means (20) has a connection (40) made of energetic material, which is encapsulated in a sealed plastic or glass housing (50), which is a directional release agent (52 ) which is directed in a selected direction (x) and has an effective distance (a) from the connection (40) which is substantially smaller than the rest of the closed housing (50) and that a voltage pulse with an initial voltage of over 500 V and a constant voltage, the connection (40) causes an electric arc to be generated in a termination at ho forth temperature and high pressure occurring exothermic reaction to form a plasma and that the effective distance (a) of the release agent (52) is thick enough to include said exothermic reaction until the formation of the plasma and thin enough to the plasma enable the direction-controlling separating means (52) to be broken through and to penetrate through it and to act on the base charge (14). 2. Igniter according to claim 1, characterized in that a cavity (30) is provided between the separating means (52) and the base charge (14), which allows an increase in pressure and heat of the plasma stream. 3. Detonator according to claim 1 or 2, characterized characterized in that the compound (40) contains energetic metals. 4. igniter according to one of claims 1 to 3, characterized in that the energetic metals are selected from the class consisting of gallium arsenide, aluminum gallium arsenide, gallium phosphide, lithium / iodine, a gold-added gallium component, other gallium compositions and other compounds of groups 111 to V contains. 5. Igniter according to one of claims 1 to 4, characterized in that the connection (40) is a pn junction. 6. Igniter according to one of claims 1 to 5, characterized in that the connection (40) has a pressure-resistant protective or back plate (42) which is encapsulated in the closed plastic housing (50) and arranged on that side of the connection (40) which is opposite to the selected direction (x). 7. Detonator according to one of claims 1 to 6, characterized in that the pressure-receiving back plate (210) is separated from the connection (204). 8. Detonator according to one of claims 1 to 7, characterized in that the connection (40) is a pn junction and that the pressure-receiving back plate (42) is a first electrode of this pn junction. 9. Detonator according to one of claims 1 to 8, characterized in that the back plate (42) is concave and is turned with its concave side in the selected direction. 10. Detonator according to one of claims 1 to 9, characterized in that a second electrode (44) of the connection (40) consists of gold and is arranged between the back plate (42) and the direction-controlling separating means (52). 11. Detonator according to one of claims 1 to 10, characterized in that the back plate (42) is designed as a focusing means for focusing the plasma formed from an arc in the selected direction. 12. Detonator according to one of claims 1 to 11, characterized in that the separating means (52) is formed by a shaped recess (52 or 130 or 310) in the sealed plastic housing (50). 13. Detonator according to one of claims 1 to 12, characterized in that the recess has an inner, generally flat surface (52 or 214 or 234). 14. Detonator according to one of claims 1 to 13, characterized in that the recess (52 or 214 or 234) is substantially circular and has a substantially conical outer peripheral surface (54). 15. Detonator according to one of claims 1 to 14, characterized in that the separating means (52) directly opposite the connection (40) has a predetermined breaking point (62). 16. Detonator according to one of claims 1 to 15, characterized in that a safety barrier (16) is arranged on the base charge (14) and at a selected distance (b) from the separating means (52). 17. Detonator according to one of claims 1 to 16, characterized in that the safety barrier (16) is a copper layer. 18. Igniter according to one of claims 1 to 17, characterized in that the connection (40) has first and second electrodes (206 and 208, respectively) which are aligned with the edges of the recess (212). 19. Detonator according to one of claims 1 to 18, characterized in that the plastic housing consists of a clear epoxy plastic. 20. Detonator according to one of claims 1 to 19, characterized in that the connection (40) has a gold electrode which evaporates during the formation of the plasma. 21. Detonator according to one of claims 1 to 20, characterized in that the base charge (14) is a hollow tube (150) which has a highly explosive powder explosive (156) on its inner surface and the open end (152) of the release agent (52 ) is facing (Fig. 7). 22. Detonator according to one of claims 1 to 21, characterized in that the open end (152) of the hollow tube (150) is cut off at an angle to the axis of the tube (150). 23. Igniter according to one of claims 1 to 22, characterized in that the connection (40) is a pn junction in an epoxy-encapsulated LED device and that the direction-controlling separating means (52) has a reduced wall on the light output side of the encapsulated LED device is. 24. Detonator according to one of claims 1 to 23, characterized in that the effective distance (a) is greater than 1/32 ". 25. Detonator according to one of claims 1 to 24, characterized in that the effective distance (a) is approximately in the range of 1/32 to 3/32 ". 26. Detonator according to one of claims 1 to 25, characterized in that the effective distance (a) is approximately 1/16 ". 27. Detonator according to one of claims 1 to 26, characterized in that the pulse voltage is in the range of 1 - 4 kV. 28. Detonator according to one of claims 1 to 27, characterized in that 10 us after the application of the energy to the detonator of the voltage pulse still has at least 50% of the initial voltage. 29. Detonator according to one of claims 1 to 28, characterized in that the capacitance forming the voltage pulse is approximately 0.1 µF up to approximately 10 - 20 µF. 30. Igniter according to one of claims 1 to 29, characterized in that the capacitance forming the voltage pulse at an initial voltage of about 1000 V 0.1 µF up to 10 - 30 µF and for initial voltages between 500 and 1000 V about 100 - 300 µF is. 31. A method for detonating the base charge in an electrically ignitable detonator with the following method steps: a) providing an element generating an electric arc; b) encapsulating this element in a sealed plastic or glass housing; c) changing said plastic or glass housing on a surface to define a breakout point; d) applying a voltage pulse to said element, the voltage pulse having an initial value of 1 - 4 kV, which is created in less than about 1 µs and which is held at over 50% of said initial value for at least 5 - 10 µs, and e) Alignment of the electric arc and the resulting plasma, which originates from the breakout point, on the base charge 32. Method for producing an igniter for an electrically operated detonator, characterized by the following method steps: a) providing an LED with two connecting lugs encapsulated in an epoxy housing, a pn junction and light output tip on the epoxy resin or glass housing; b) Remove the light output tip to create a thin wall over the pn junction, the thickness of which is between 1/32 "and 3/32", preferably 1/16 ".

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