OA12485A - Programmable pyrotechnical firing installation. - Google Patents

Description

1 012485

Programmable pyrotechnical firing installation

In mines and quarries the breaking of rocks is typically carried out by means ofexplosives. A firing program consists of making a plurality of drill-holes in the rock, which 5 are filled with explosives with, for every drill-hole, a detonator that permits thefiring. Some of these detonators are electronically controlled, which makes itpossible to program the setting off of the explosions according to a predeterminedfiring plan.

The execution of a firing plan consists, therefore, after having arranged ail the W detonators in the drill-holes that hâve been made and connecting them to a controlunit, of identifying every detonator by a serial number and applying to it a delaytime which will détermine the ignition of the charge in relation to a general firingsignal.

The présent invention relates to such a programmable pyrotechnical firing 15 installation, in which ail the detonators are connected to the control unit by wires.

Conventionally, an electronic detonator comprises a pyrotechnical percussion cap,an energy reserve, an electronic pilot and two electrical conductors that connectthe electronic pilot to a firing line which runs over the ground from a centralprogramming and control unit; The electronic pilot comprises an on-board 20 microprocessor by means of which communication can be established hetween thedetonator and the central unit. The microprocessor is programmed or program-mable so as to be able to receive requests issued in the firing line by the centralunit and to respond to these requests either in the direction of the central unit or inthe direction of the energy reserve, which it will release with a spécifie time delay 2 012485 when the firing order has been received from the central unit. The programming ofthe on-board microprocessor in the electronic pilot of the detonator can be carriedout a priori before its positioning in the firing fîeld or, as is the case for theinvention, a posteriori after it has been put into position. The firing line on theground also serves to provide the electrical energy required for filling the energyreserve, which takes place just before the firing in order to comply with the safetyrequirements that demand that the detonators must be inactive up to the lastmoment.

It must be borne in mind that a firing line may hâve a length of about a kilométré.For this reason, with the current installations it is relatively simple to transmitfrom the control unit signais to the address of every detonator, however far thismay be removed from the control unit, since the required energy to be providedfor these signais so that they will reach their target is controlled totally from thecontrol unit. On the other hand, a detonator has very little on-board energy and ifone wantsittobe ableto respond to the central unit, it will be noted that thelimited power of the signais which it emits suffers a strong atténuation that maymake them inaudible by the central unit if the detonator-emitter is far away fromsame on the firing line.

The présent invention provides a solution to this bi-directional communicationproblem between a central unit and each one of the detonators of a fïring line, asimple and economical solution.

To this end, the invention relates to a programmable pyrotechnical firinginstallation comprising a programming and control unit for the firing, aprogramming and control line comprising two conductor wires and a plurality ofelectronic detonators mounted in parallel on this two-wire line, wherein theprogramming unit comprises means for establishing a continuous voltage between 012485 the two wires, means for producing puises ofthis voltage s o asto form coded signais and means for reading the current variations existing on the two-wire line and wherein every detonator comprises an electronic module that, in response to certain o f the c oded s ignals of the programming unit corresponding to requests 5 from same, can produce current puises in the two-wire line for forming codedsignais.

In other words, when a detonator, whatever its position on the fîring line, mustrespond to a request of the central unit, it will produce in the fïlar fîring line excesscurrent peaks, for example b y closingthe line on a calibrated resistor withina W given time and this in dependence on a puises program corresponding to a codegenerated by the on-board microprocessor, which excess current peaks areimmediately détectable by the central unit, which by means of a resistor willconvert them into a modulated voltage that can be interpreted by its micro-processor, this forming the response of the detonator in question to the request of 15 this central unit.

Other characteristics and advantages of the invention will be noted from thedescription given below by way of non-limitative example, of an exemplifiedembodiment. ·" —

Reference will be.made to the attached drawings, wherein: 20 - Figure 1 is a diagram illustrating a pyrotechnical fîring installation,

Figure 2 illustrâtes diâgrammatically a central programming and control unitof the installation,

Figure 3 is a functional diagram of that part of the electronic pilot of everydetonator involved in the dialogue with the central programming and controlunit. 25 012485 Το carry out a firing program, holes 1 are drilled in a rock 2 from, for example, the ground 3. In each of these drill-holes 1, detonators 4 and explosive charges 5 are placed, every detonator 4 being connected to firing line 6 on the ground by conductors 7. A central programming and control unit is shown at 8, connected to 5 the firing line 6.

This unit 8, see figure 2, comprises a microprocessor 9 which acts on a device 10for the supply of a continuous voltage between the two wires 6a, 6b of the line 6and which permits inserting into this continuous voltage drop sequences so as toform slots corresponding to any type of binary code of a signal. Furthermore, the 10 central unit 8 is provided with a device 11 for converting into voltage the currentcirculating on the line 6a, 6b in order to produce variations of this current that canbe understood by the microprocessor 9.

The electronic pilot 12 of the detonator illustrated diagrammatically and partiallyin figure 3, comprises a voltage regulator 13, the input of which is connected to 15 the line 6a, and the output to an on-board microprocessor 14, in order to form apower supply of this microprocessor 14 increased by a capacitor 15 that permitssmoothing the drops in voltage in the line 6. This pilot 12 also comprises a circuit16 for detecting codes carried by the line 6, the input of which is also connected tothe line 6a and the outlput of which is directed towards the microprocessor 14. 20 Between the lines 6a and 6b the electronic pilot 12 has a voltage-drawing circuit17, for example a transistor and a resistor, controlled by the microprocessor 14.Finally, the microprocessor 14 Controls a switch 18 of the line 6a, in a manner aswill be explained below. 5 012485

Each one of the detonators 1 is connected to the two-wire line 6a, 6b parallel to same at the point A, B (figure 3). In reality, four wires 19, 20, 21, 22 corne from this electronic pilot 12, which form the conductors 7 of figure 1. The wires 19 and 20 permit connecting the pilot to the wires 6a and 6b of the firing line. The line 6a 5 has a section 23 inside the pilot 12, which c omprises the switch 1 8 and whichcornes out of the pilot by way of the line 21 which becomes 6a at the level of theground. In the same manner the line 6b has a section 24 inside the pilot, which byway of the conductor 22 cornes out of the drill-hole to form the wire 6b of thefiring line at the level of the ground. At the time when the detonators are 10 positioned in the drill-holes, the switch 18 is open. The electronic pilots areconnected the one following the other. Understood under this mounting method isthat the first detonator connected to the unit 8 is mounted in sériés on the line 6a,6b when the switch 18 is open. When the switch 18 is closed, this detonator ismounted in parallel with the next one on the line 6a, 6b. 15 When the firing line has been realised, the central unit 8 establishes a voltage of,for example, 24 or 48 volt at the terminais of the conductors 6a, 6b. This voltage,regulated by the device 13, constitutes the power supply of the processor 14 aswell as the charge of the capacitor 15. By cutting this voltage by mèàns of thedevice_10, the microprocessor 9 of the central unit 8 transmits to the pilot 12 a 20 serial number recorded by the microprocessor 14, and a certain delay time. Theoperating sequence of the microprocessor 9 may then comprise a request (a binarysignal on the voltage of the line 6) to which the microprocessor 14 will respond byacting on the current-drawing circuit 17 to create excess voltage peaks which,converted by the device 11, will be assimilated as a response to the request by the 25 microprocessor 9. The last order transmitted by the microprocessor 9 to the on-board microprocessor 14 will be to close the switch 18. At this moment, the pilot 012485 of the next detonator is in the same State with regard to the central unit 8 as thepreceding pilot and the programming sequence can recommence.

When ail the detonators hâve been programmed in this manner, the fîringinstallation is ready to operate. The microprocessor 9 may comprise in its program 5 other stages and other requests conceming the detonators. It will then transmit ageneral order to ail the detonators to proceed with the charging of the energyreserve, not illustrated in the figures, possibly followed by a v erification of theState of this reserve, and will finally transmit to ail the detonators a fîring signal.

Claims (2)

1. 012485 CLAIMS

   1. A programmable pyrotechnical fïring installation comprising a programmingand fïring control unit (8), a programming and control line comprising twoconductor wires (6a, 6b) and a plurality of electronic detonators (12) mountedin parallel on this two-wire line, characterised in that the programming unit 5 (8) comprises means (9,10) for establishing a continuons voltage between the two wires (6a, 6b), means (9,10) for producing puises of this voltage so as toform coded signais and means (11, 9) for reading the current variationsexisting on the two-wire line and in that every detonator comprises anelectronic module (12) that has means (14, 17) suitable for producing, in 10 response to certain of the coded signais of the programming unit (8), current puises in the two-wire line (6a, 6b) for forming coded signais.
2. 2. A fïring installation according to claim 1, characterised in that everyelectronic detonator module (12) comprises a switch (18) of the two-wire line(6a, 6b), which normally is open and is closed in response to a signal emitted 15 by the programming unit (8).