EP0681158A1 - Explosive chain - Google Patents

Abstract

An explosive chain for use in particular in mining has a plurality of ignition stages S1, S2, ..., each of which contains a series circuit comprising a thyristor T and an ignition device Z1, which is located between two supply lines A, O and B, O, respectively. The signal voltage for the thyristor T of each stage is derived solely from the switching state of the thyristor T of the previous stage. As a result, the forwarding of the activation from stage to stage becomes independent of the ignition device Z1, in particular regardless of whether an igniter is connected at all and whether it becomes properly high-resistance or not when activated. In this way, errors in known circuits are avoided, which can lead to the fact that when the power supply is switched on, the blasting begins not only at the first ignition stage but also at the location of a missing igniter, or that the explosion sequence ends at the location of an improperly functioning igniter or that there are inadmissible delays and thus an excessive shortening of the distance between the electrical sequence and the explosion wave and undesirable changes in the pressure wave triggered by the blasting sequence. <IMAGE> <IMAGE>

Description

The invention relates to an explosive chain with a plurality of ignition stages to be controlled in sequence, to which explosive devices are assigned. Such explosive chains are used in particular in mining, where, for example, a hundred or more boreholes are attached to the collision, an explosive device with an associated detonator is inserted into each, and the boreholes are closed with plugs. In order to ensure effective dismantling, it is important that the explosive devices detonate one after the other in a predetermined order, the time interval between successive firings typically being between 30 and 50 ms.

From US-A-4 099 467 an explosive chain is known in which each ignition stage contains an igniter and a thyristor switch connected in series therewith, the control electrode of which is connected to the tap of a voltage divider containing the igniter of the preceding stage. If the previous igniter is activated, its resistance changes from an initially low value to practically infinite, whereby the thyristor switch of the following stage switches through and the next current pulse triggers the igniter in series with it.

Parallel to each detonator is a fuse, which is to ensure that the change in resistance required to trigger the next stage and thus to advance the detonating chain also occurs when there is no detonator at one point. However, this fuse forms a short-circuit bridge and increases the power requirement considerably.

Another difficulty is that such a fuse represents an additional discrete component to be inserted into each ignition stage. If the fuse in a printed circuit is implemented by a weak conductor track section, then the Printed circuit board to maintain exact tolerances, which leads to an increase in price.

If a detonator is connected, but defective in such a way that, despite triggering, it does not become high-resistance not immediately, but only when the assigned explosive charge is detonated (usually between 0.5 and 1.5 s later), this results in an excessively long delay within the explosive chain, so that the pressure wave cannot spread in the programmed manner at the shock absorber. In such a case, the reliability of the explosive chain is also significantly reduced, since the distance between the electrical sequence and the explosion wave is greatly shortened.

Similar problems exist with the explosive chain known from US-A-4,760,791. Here, a transistor is connected in parallel to each igniter, which, when there is no igniter, carries current in its place and prevents the ignition sequence from being interrupted at the location of a missing igniter. In addition to the parallel connection of igniter and transistor, there is a fuse in series, which is intended to prevent an igniter which does not immediately become high impedance from delaying the pulse transmission until the actual detonation. The difficulties described above also exist with this known explosive chain.

An even more serious problem is that a further transistor is used in such a way that it alloys when the circuit is operated as intended in order to establish a short-circuit connection for the ignition current pulse. Since the transistor is destroyed in this case, no function test can be carried out on the known explosive chain before the actual use. It is also not possible to reuse the electronic circuit part of the explosive chain. Finally, there is a risk that the base connections of this transistor, which are not very resilient, will be blown away by the considerable currents before the igniter is activated.

In addition, it is necessary to insert a separate activation link at the beginning of the chain, so that it is not possible to produce explosive chains of the desired length simply by cutting off a greater length or joining shorter pieces together.

DE-B-2 356 875 describes a further explosive chain in which each ignition stage contains an oscillator, a frequency divider and two driver stages in addition to the actual igniter. The trigger pulse coming from the respective previous ignition stage actuates the first driver stage, which in turn closes a switch for controlling the oscillator, the frequency divider and the second driver stage. The output of the frequency divider supplies the trigger signal for the subsequent ignition stage in the explosive chain, while the second driver stage actuates a further switch via which the igniter is activated. Each ignition stage also contains a capacitor for storing all the energy required for ignition.

The impulse is passed on regardless of the presence and functionality of the detonator; however, the circuit requires a circuit outlay that is unacceptable for practical explosive chains.

From DE-B-1 287 495 an explosive chain with the features specified in the first part of claims 1, 2 and 9 is known, in which the transmission of the control signal from one ignition stage to the next solely by changing the switching state of the provided in each stage Semiconductor switch is effected. This explosive chain therefore remains functional even if individual detonators are missing or do not become properly high-resistance. Since each semiconductor switch can only become conductive and can activate the ignition device assigned to it when the semiconductor switch has switched to the previous stage, the intended ignition sequence is inevitably adhered to. Incorrect assembly of the explosive chain cannot lead to the fact that when the power source is switched on the explosive chain starts to ignite at two different points at the same time.

The known explosive chain, however, requires in each ignition stage at least one capacitor for the pulse transmission from one ignition stage to the next. Because of these capacitors, the known circuit cannot be fully integrated.

In addition, this circuit also requires its own switching element upstream of the first ignition stage to initiate the chain, so that it cannot be extended or shortened at least on the side of the first ignition stage.

An object of the invention is to provide an explosive chain which on the one hand has the advantage that it works properly even when an igniter is not provided or is faulty at individual points, in particular does not immediately become high-resistance when activated, and on the other hand it is implemented in integrated circuit technology favored.

The solution to this problem is specified in claim 1. The explosive chain formed afterwards manages with an uncomplicated circuit without capacitors, can therefore be easily integrated, and nevertheless fulfills all requirements for operational safety even if the assembly is incorrect or incorrect.

Another solution to this problem is given in claim 2. In this circuit, the same capacitor is used for two successive firing stages, so that the entire explosive chain requires only half as many capacitors as the prior art, without being inferior in operational safety.

Claims 4 to 7 relate to various possibilities for providing the first stage in the firing sequence with a start pulse. The measure of claim 5 is advantageous insofar as it allows all ignition stages to be constructed in the same way with minimal switching effort of the explosive chain. An explosive chain for a desired number of Accordingly, detonations can simply be cut off from a longer or continuously produced arrangement, or can be generated by adding shorter lengths.

The design according to claim 8 is expedient insofar as the explosive chain links surrounded by one housing are the same and incorrect wiring of the individual ignition stages is avoided.

Another object of the invention is to provide an explosive chain, which in turn has the advantage of the known circuit that it works properly even when an igniter is not provided or faulty at individual points, but which does not need its own initial circuit element.

The solution to this problem is specified in claim 9. In this solution, all ignition stages or pairs of ignition stages can be constructed identically; nevertheless, the ignition starts at the first ignition stage of the chain when the power source is switched on, without special measures being required for the initial ignition.

Figur 1

einen Teil einer Sprengkette gemäß einem ersten Ausführungsbeispiel,

Figur 2

eine der Figur 1 ähnliche Darstellung eines zweiten Ausführungsbeispiels,

Figur 3

eine Variante der Schaltung nach Figur 2,

Figur 4

ein weiteres Ausführungsbeispiel einer Sprengkette,

Figur 5

ein Impulsdiagramm der von einer Stromquelle zum Betrieb der Sprengkette nach Figur 4 erzeugten Stromimpulse,

Figur 6

eine Ausgestaltung für die in der Zündfolge erste Zündstufe, und

Figur 7

eine Variante der Sprengkettenschaltung nach Figur 2 mit einer weiteren Maßnahme zur Auslösung der ersten Zündstufe.

Embodiments of the invention are explained below with reference to the drawings. In the drawings shows

Figure 1

a part of an explosive chain according to a first embodiment,

Figure 2

1 shows a representation of a second exemplary embodiment, similar to FIG. 1,

Figure 3

a variant of the circuit of Figure 2,

Figure 4

another embodiment of an explosive chain,

Figure 5

4 shows a pulse diagram of the current pulses generated by a current source for operating the explosive chain according to FIG. 4,

Figure 6

a configuration for the first ignition stage in the firing sequence, and

Figure 7

a variant of the explosive chain circuit according to Figure 2 with a further measure to trigger the first ignition stage.

1, the individual ignition stages S1 , S2 ,... Lie parallel to one another and in each case between two supply lines A and O , which are connected at the right-hand end in FIG. 1 to a DC power source (not shown). The DC power source produces an output voltage of 50 V on line A with respect to grounded line O.

Each of the identically constructed ignition stages S1 , S2 , ... contains a series circuit between a supply line A , O consisting of a thyristor T and an ignition device ZE , which has two detonators Z1 , Z2 connected in series. Each detonator Z1 , Z2 is used to trigger an explosive charge (not shown). In the circuits described here, detonators with a built-in delay of 0.5 to 1.5 s are used.

The control electrode of the thyristor T is connected via a Zener diode ZD (Zener voltage: 35 V) at the connection point P between a resistor R1 (2.2 KΩ), whose other end is connected to the supply line A , and a capacitor belonging to the previous ignition stage S1 C (22 µF), which is connected to the supply line O with its other electrode. The connection point P is also connected via a diode D to the connection point between the thyristor T and the ignition device ZE of the previous ignition stage. A resistor R2 (100 Ω) is connected between the control electrode and the cathode of the thyristor T. Another resistor R3 (5 Ω) lies between the connection point of the cathodes of the thyristor T and the diode D on the one hand and the ignition device ZE . A fourth resistor R4 (470 Ω) bridges the ignition device ZE .

The resistors R1 and R4 are dimensioned so that when the voltage of 50 V is applied to the line A, the potential at the connection point P is not sufficient for the thyristor T Switch through stage S2 . Only when the thyristor T of the preceding stage S1 conducts does the point P reach a potential (50 V minus the voltage drop across the thyristor T and across the diode D ) at which the capacitor C rises to such a high level via the resistor R1 Value can charge that the ignition voltage for the thyristor T of stage S2 is reached. Taking into account the Zener voltage (35 V) of the Zener diode ZD, this value is approximately 15 V, which is sufficient for switching the thyristor T.

The delay with which the thyristor T of stage S2 becomes conductive after the thyristor T of stage S1 has been switched on depends on the time constant of the RC element formed by resistor R1 and capacitor C. The required delay of 30 to 50 ms can be achieved by appropriate dimensioning.

As can be seen from the above description, the transmission of the trigger pulse from stage to stage with the specified delay time is independent of the ignition device ZE . This means that the circuit works properly even if one or several ignition stages has been forgotten to insert an ignition device.

The same applies if an ignition device is present but does not work properly and does not immediately become high-resistance when it is acted on. In this case, the detonator would maintain its very low original resistance until the actual explosive charge explodes (and thus destroys the detonator). In practice it has been shown that a few percent of all detonators show this behavior.

If two detonators Z1 , Z2 are connected in series, as is assumed in FIG. 1, the probability that both detonators display this malfunction is extremely low. In this way it can be practically avoided with certainty that short-circuit current is drawn from the current source during the entire period from switching on the thyristor T to detonation of the explosive charge (that is to say for about 0.5 to 1.5 s) becomes. The resistor R3 is provided for the very rare case that the two igniters Z1 , Z2 in series become high-resistance at the same time.

In the explosive chain according to FIG. 1, all ignition stages S1 , S2 , ... are constructed identically. It is therefore possible to produce explosive chains with a desired number of ignition stages by simply cutting them off from a greater length. In this case, the capacitor C for generating the ignition voltage, which is otherwise in the previous stage, is missing in the first stage in the firing sequence ( S1 in FIG. 1). The ignition of the first stage S1 takes place without delay when the supply voltage is applied to the line A via the Zener diode ZD and the resistor R3 , since the circuit elements D , R3 and R4 of a previous stage are not present.

The circuit according to FIG. 2 differs from that according to FIG. 1 in that a current source is used which alternately gives current pulses on two channels to which the supply lines A and B are connected, which preferably do not overlap one another. The ignition stages are alternately connected to the supply lines A and B.

In the circuit according to FIG. 2, the ignition delay from one stage to the next is thus predetermined by the pulse current source. The individual ignition stages S1 , S2 , ... therefore do without an RC element, and the resistor R1 present in FIG. 1 can be omitted. Furthermore, the Zener diode ZD provided in FIG. 1 is replaced in the circuit according to FIG. 2 by a resistor R5 (1 KΩ).

Since each ignition stage is activated in FIG. 2 only when the thyristor T has become conductive due to a corresponding signal on its control electrode and a pulse is present on the supply line A or B , it is not necessary to provide a series connection of two detonators as the ignition device . Even if the individual detonator does not become properly high-resistance when activated, the power consumption is limited to that short time interval (for example 10 to 20 ms) during which the current pulse is present on the supply line A , B.

In the circuit according to FIG. 2, the parallel connection of two detonators Z1 and Z3 with a respective series resistor R3 is assumed as a variant. This parallel connection only represents an economy measure. In such a case, two detonators are acted on simultaneously, so that the correspondingly assigned explosive charges detonate simultaneously. The resistor R3 enables the thyristor T to turn on even when the respective igniter Z1 , Z3 is short-circuited and to charge the capacitor C of the subsequent stage.

Otherwise, similar to the circuit of FIG. 1, the capacitor C (4.7 μF) only charges when the thyristor T of the previous ignition stage is conductive. At a certain potential of the capacitor C , the ignition voltage for the thyristor T is reached, so that the latter is switched through by the subsequent current pulse on the associated supply line A , B.

In FIG. 2, a resistor R1 is shown in the first ignition stage S1 , which is connected to the same supply line A as the thyristor T of the first ignition stage S1 . This resistor R1 is used in connection with a corresponding overvoltage pulse (80-100 V / 1 ms) on the supply line A for the initial ignition of the explosive chain.

If you want to build the explosive chain consistently in the same way, an identical resistor R1 can be provided for all ignition stages S1 , S3 , ... which are connected to the same supply line ( A ). Such a resistor R1 (which is not required for the function of the circuit) is shown in dashed lines in the ignition stage S3 in FIG.

With a pulse duration of 1 ms, it is impossible to switch through for all subsequent stages, since the associated capacitor C is only charged to approximately 5 V. Only the first stage S1 , which does not contain a capacitor, can switch through with such a short pulse. This ensures that the firing sequence always begins at the beginning of the chain.

The circuit according to FIG. 3 is largely similar to that according to FIG. 2, but differs in that a common capacitor is provided for two successive ignition stages. In FIG. 3, this is the capacitor C (4.7 μF) located in the ignition stage S1 , which is used to generate the control voltages for the thyristors T of the ignition stages S2 and S3 . Otherwise, the circuit of FIG. 3 is the same as that of FIG. 2, the diode D being replaced by a resistor R6 (2.2 KΩ).

The end of the capacitor C facing away from the supply line O is connected to the control electrode of the thyristor T of stage S2 via a resistor R5 (1 KΩ) as in FIG. The same electrode of the capacitor C is also connected via a resistor R7 (4.7 KΩ) and the resistor R5 (1 KΩ) to the control electrode T of the ignition stage S3 .

If resistor R1 is not provided, the two series resistors R7 and R5 could also be combined to form a resistor (5.7 KΩ). The embodiment shown in FIG. 3 was chosen for the reasons described above for the equality of all the links in a chain, again the resistance R1 (5 KΩ) shown in broken lines in stage S3 is not necessary for the function.

As soon as the thyristor T of the ignition stage S1 conducts, the capacitor C charges up to about 15 V via the resistor R6 . This value is sufficient to ignite the thyristor T of stage S2 . If the thyristor T of stage S2 switches on at the next current pulse on the supply line B , the capacitor C is further charged to about 34 V via the resistor R2 (100 Ω) and the resistor R5 (1 KΩ), which now takes into account the resistors R7 and R5 are sufficient to ignite the thyristor T of the ignition stage S3 , which then switches on when the next pulse occurs on the supply line A.

In the circuit according to FIG. 3, as in FIG. 2, two ignition units connected in parallel can be provided in each ignition stage. Likewise, the initial ignition of the first stage S1 can take place via the resistor R1 provided there and an initial overvoltage pulse on the supply line A.

The circuit according to FIG. 1 works with a capacitor in order to achieve the desired delay of 50 ms between the successive ignition stages. The timer consists of the resistor R1 and the capacitor C , and the switching threshold (35 V) is determined by the Zener diode ZD .

The circuits of Figures 1 and 2 use a capacitor to pass the switching pulse from one stage to the next and to store (about 1 to 2 ms) during the gap between successive pulses on lines A and B. In the further circuit according to FIG. 4, this memory function is taken over by the thyristor itself.

The circuit according to FIG. 4 is identical to that according to FIG. 2, the diode of FIG. 2 being replaced by a resistor R6 (2.2 KΩ) similar to FIG. 3 and a resistor R8 (1 KΩ) being provided instead of the capacitor C.

A further difference from the circuits according to FIGS. 2 and 3 is that the pulses supplied by the current source via the supply lines A , B connect directly to one another in time and each pulse according to FIG. 5 has an initial interval of reduced voltage which corresponds to the previous pulse on the respective other supply line overlaps.

During the time interval shown in Figure 5 t₀∼t₂, in which the full pulse (50 V) occurs on the supply line A , the thyristor T of the ignition stage S1 is turned on . Before the end of this time interval occurs at the time t₁ the reduced initial voltage interval (20 V) of the next pulse on the supply line B , so that now the thyristor T of stage S2 ignites. The other Voltage occurring at the cathode (20 V), however, is not sufficient to also ignite the thyristor T of the next stage S3 , which per se is charged with the full voltage of the pulse on line A. Only after the pulse on line A has been switched off at the time t 2, the pulse on line B rises to the full voltage (50 V) at the time t 3, so that the thyristor T of the stage S2 can now switch on fully and which is used for ignition of the thyristor T of the next stage S3 supplies the required voltage.

As with the circuits according to FIGS. 2 and 3, a further resistor R1 (10 KΩ) is also present in the circuit according to FIG. 4 in the first stage S1 , which is used in conjunction with the first overvoltage pulse shown in FIG. 5 for the initial ignition of the explosive chain.

Again, the same resistor R1 is not required for the function of the circuit in the other stages with the exception of the first ignition stage S1 and is therefore only shown in broken lines. As above, it can be provided in order to be able to construct the entire ignition chain from identical links. Likewise, two igniters connected in parallel can also be provided in the circuit according to FIG. 4 in the ignition stage.

FIG. 6 shows a variant for the first ignition stage S1 of an explosive chain, which is otherwise constructed in accordance with FIG. 2. The same variant is also suitable for the circuits according to FIGS. 3 and 4.

In the circuit according to FIG. 6, the resistor R1 shown in FIG. 1 is replaced by a parallel circuit consisting of a resistor R1 ' (> 100 KΩ) and a capacitor C2 (1 μF). It is thereby achieved that only the first pulse of 50 V given to the supply line A can ignite while the capacitor C2 is still empty in the thyristor T of the first stage S1 . The resistor R1 ' causes the capacitor C2 to discharge so slowly that all further pulses on the supply line A no longer reach the control electrode of the thyristor T.

In the circuit according to FIG. 6, the first ignition stage S1 of the explosive chain has a special configuration; this means that the explosive chain begins to work as soon as the pulse current source is switched on without an overvoltage initial pulse being required; on the other hand, it is no longer possible to produce a functional explosive chain simply by cutting off a longer, prefabricated explosive chain.

In the circuit variant shown in FIG. 7, the thyristor T of the first stage S1 can also be ignited without an initial overvoltage pulse. The circuit according to FIG. 7 presupposes that a current pulse is briefly generated on both lines A , B for initial ignition, which current pulse is added via the two resistors R1 , R1 ″ (10 KΩ each) provided here. With this version it is again possible to assemble the entire explosive chain from identical links and thus to obtain a functional explosive chain by simply cutting off a greater length, provided that the resistances R1 , R1 '' are doubled at every (or every other) ignition stage becomes.

2 to 4, the even-numbered ignition stages are identical to one another and likewise the odd-numbered ignition stages are identical to one another. In order to ensure that when an explosive chain of this length is cut off, an ignition stage of the correct type forms the first stage of the chain, or when two similar ignition stages are not joined together, successive stages can be arranged in pairs in common housings (not shown).

The dimensions of the various circuit elements given in parentheses in the preceding description of the figures only represent typical values of exemplary embodiments.

Claims (12)

Explosive chain with successively controlled ignition levels ( S1 , S2 , S3 , ...), whereby
each ignition stage ( S1 , S2 , S3 , ...) has an ignition device ( ZE ) for igniting at least one explosive device in series with the output circuit of a semiconductor switch ( T ),
the series circuits thus formed are connected in parallel between supply lines ( A , B , O ) connected to a current source, and
the control input of the semiconductor switch ( T ) of each ignition stage ( S2 , S3 , ...) is connected to the connection point between the semiconductor switch ( T ) and the ignition device ( ZE ) of the respective previous ignition stage ( S1 , S2 , ...),
characterized by
that the supply lines ( A , B , O ) are divided into two channels ( A , O ; B , O ) alternately fed by pulses from the power source and successive ignition stages ( S1 , S2 , S3 , ...) alternately to one and the other other channel are connected, and
that each pulse on one channel has a previous pulse overlapping the previous pulse on the other channel initial interval (t₁∼t₃) lower voltage. Explosive chain with successively controlled ignition levels ( S1 , S2 , S3 , ...), whereby
each ignition stage ( S1 , S2 , S3 , ...) has an ignition device ( ZE ) for igniting at least one explosive device in series with the output circuit of a semiconductor switch ( T ),
the series circuits thus formed are connected in parallel between supply lines ( A , B , O ) connected to a current source, and
the control signal for the semiconductor switch ( T ) of each ignition stage ( S2 , S3 , ...) is the voltage of a capacitor ( C ) which can be charged via the semiconductor switch ( T ) of the previous ignition stage ( S1 , S2 , ...) ,
characterized by
that the supply lines ( A , B , O ) are divided into two channels ( A , O ; B , O ) alternately acted upon by the power source and successive ignition stages ( S1 , S2 , S3 , ...) alternately on one and the other channel are connected, and
that a common capacitor ( C ) is provided for each pair of successive ignition stages ( S1 , S2 ), which is set to a first value via the semiconductor switch ( T ) of the ignition stage preceding this pair and via the semiconductor switch ( T ) of the first ignition stage ( S1 ) of the pair can be charged to a second, higher value. The explosive chain according to claim 2, wherein the capacitor ( C ) with the control input of the semiconductor switch ( T ) of the first ignition stage ( S1 ) of the pair via a first resistor ( R5 ) and with the control input of the semiconductor switch ( T ) second ignition stage ( S2 ) of the pair via a first resistor ( R7 ), which is larger than the first resistor ( R5 ), is connected. Detonating chain according to one of claims 1 to 3, wherein the control input and the output circuit of the semiconductor switch ( T ) are connected to the same channel in the first ignition stage ( S1 ) in the firing sequence. The explosive chain according to claim 4, wherein the current source for controlling the first ignition stage ( S1 ) in the firing sequence delivers an overvoltage pulse. Detonating chain according to claim 4, wherein the control input of the semiconductor switch ( T ) is connected to the relevant channel via an RC element ( R1 ' , C2 ) in the first firing stage ( S1 ) in the firing sequence. The explosive chain according to claim 4, wherein the control input of the semiconductor switch ( T ) is connected to both channels in the first firing stage ( S1 ) in the firing sequence and the current source for triggering the first firing stage ( S1 ) generates a pulse on both channels. Detonating chain according to one of claims 1 to 7, wherein two ignition stages ( S1 , S2 ; ...) are combined to form a circuit element arranged in a common housing and all circuit elements are constructed identically, and only the first ignition stage ( S1 ) in the ignition sequence, in which there is no previous stage, can be activated by an initial pulse. Explosive chain with successively controlled ignition levels ( S1 , S2 , S3 , ...), whereby
each ignition stage ( S1 , S2 ) has an ignition device ( ZE ) for igniting at least one explosive device in series with the output circuit of a semiconductor switch ( T ) and a first resistor ( R4 ) is connected in parallel with the ignition device ( ZE ),
the series circuits formed from an ignition device ( ZE ) and a semiconductor switch ( T ) are connected in parallel between supply lines ( A , O ) connected to a current source, and
the control signal for the semiconductor switch ( T ) of each ignition stage ( S2 , S3 , ...) is the voltage of a capacitor ( C ) which is in the conductive state of the semiconductor switch ( T ) of the previous ignition stage ( S1 , S2 , ... ) charges
characterized by
that the capacitor ( C ) is connected in series with a second resistor ( R1 ) between the supply lines ( A , O ),
that the connection point ( P ) between the capacitor ( C ) and the second resistor ( R1 ) of each ignition stage ( S2 , S1 , ...) via a diode ( D ) with the connection point between the semiconductor switch ( T ) and the first resistor ( R4 ) of the previous ignition stage ( S1 , S2 , ...) is connected, and
that the first and second resistors ( R4 , R1 ) are dimensioned such that the capacitor ( C ) only charges to a voltage required to switch the semiconductor switch ( T ) of the relevant ignition stage ( S2 , S3 , ...), when the semiconductor switch ( T ) of the previous ignition stage ( S1 , S2 , ...) conducts. Explosive chain according to claim 9, wherein the current source between the supply lines ( A , O ) generates a DC voltage and all ignition stages ( S1 , S2 , S3 , ...) are connected in parallel. Detonating chain according to one of the preceding claims, wherein each ignition device ( ZE ) contains two detonators ( Z1 , Z2 ) in series. Detonating chain according to one of the preceding claims, wherein each ignition device ( ZE ) contains two detonators ( Z1 , Z3 ) connected in parallel.

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