Explosive train used esp. in mining - has detonation stages, each contg. semiconductor switch and parallel-connected detonators

摘要

An explosive train has detonation stages (Zn), each of which is in series with the output circuit of a semiconductor switch (Tn) having an input circuit activated by resistance increase in the preceding detonation stage (Zn-1). The series circuits (Tn,Zn) are controlled by a current pulse generator. The improvement is that (i) each detonation stage (Zn) has a first detonator (Zn1) which is in series with the semiconductor switch (Tn) and which is connected in parallel with at least one series circuit of a resistor (Rn4,Rn4') and a second detonator (Zn2,Zn3), the resistor rating being greater than the resistance of a detonator which is not through-connected and is less than the resistance of a through-connected and is less than the resistance of a through-connected detonator so that the control voltage of the pulse generator is sufficient for through connection of the second detonator (Zn2,Zn3); and (ii) the pulse train contains a number of successive current pulses, transmitted by the same supply line (A,B), which is equal to the number of detonators (Zn1,Zn2,Zn3) in each detonation stage (Zn). USE/ADVANTAGE - The explosive train is used esp. for rock blasting in mining operations. It has lower circuit elements and lower wiring costs than prior art explosive trains.