WO2021229597A1

WO2021229597A1 - An electronic system for controlled sequential detonation and method thereof

Info

Publication number: WO2021229597A1
Application number: PCT/IN2021/050443
Authority: WO
Inventors: Murtaza Maimoon; Sabiha Maimoon
Original assignee: Murtaza Maimoon; Sabiha Maimoon
Priority date: 2020-05-09
Filing date: 2021-05-06
Publication date: 2021-11-18
Also published as: ZA202212906B

Abstract

Disclosed is an electronic system for controlled sequential detonation comprising: a plurality of control module(s), wherein each control module comprises of an electronic circuit connected to a detonator; and an exploder, wherein the exploder is connected to at least one control module through at least one connector; wherein, a plurality of set, each including said control module and the detonator, arranged in series/parallel such that one control module is connected to an adjacent control module in series/parallel or combination of series and parallel creating a serial detonation.

Description

AN ELECTRONIC SYSTEM FOR CONTROLLED SEQUENTIAL DETONATION

AND METHOD THEREOF

FIELD OF INVENTION

[001] The present invention generally relates to a detonation system and particularly relates to an integrated electronic system for programmable sequential detonation during activities like a mining and tunnelling.

BACKGROUND OF INVENTION

[002] The blasting operations like mining, tunnelling etc, consists of drilling of a predetermined no. of holes and charging these holes with explosives and initiators for initiating the explosives. It is desired that the holes be fired in a particular pattern (i.e. the holes are not fired simultaneously but with certain time difference between successive holes - if a hole 1 fires at a time of 10 millisecond than a hole 2 should fire at 20 millisecond and so on and so forth) for reducing vibration and improving the fragmentation of the rocks for improving the mine output.

[003] Generally, two types of detonation systems are used, one of which is non- electric detonators. The non-electric detonators are inexpensive and use two components to perform the detonation task. The first component is the surface trunkline detonators or STL which are kept on the surface. The STLs are pyrotechnic delay detonators connected with a shock tube and a J-hook connector and are attached to other STL as well as down the hole detonators or DTH. DTH are the second components which are embedded inside the explosive cartridges. DTH are also pyrotechnic delay detonators but without a j hook.

[004] Another type of detonators are electronic detonators are programmable detonators. The electronic detonation system just has 1 component i.e. no STL only DTH. The DTH in the electronic detonation system has a programmable electronic chip embedded inside the detonator which can be programmed for various delay times manually with an electronic programmer. The electronic detonation system is very accurate but is highly expensive as compared to the nonelectric system and also requires training and skilled manpower to operate.

In the prior art a PCT application WO1992008932A1 discloses an electronic control system for explosives. The said control system for detonating a plurality of blast explosives is programmable to receive and store an arming sequence and firing sequence which is compared with an operator entered command. The system generates both an ARM signal and a FIRE signal, wherein the ARM signal initiates a charge circuit (26) to charge up a detonation circuit (54) and the FIRE command releases the charge to fire the circuit. The firing sequence contains a programmable delay (66) making sequential blasting possible. The system is designed to fail safely in the event both the ARM signal and the FIRE signal do not appear within a predetermined time frame.

[005] Hence, in the view of foregoing there is a need for a detonation system with controllable sequential detonation.

[006] The above-mentioned shortcomings, disadvantages and problems are addressed herein, as detailed below.

OBJECT OF INVENTION

[007] The primary objective of the present invention is to provide a detonation system with controllable sequential detonation.

[008] Another objective of the present invention is to provide a detonation system with feasibility of estimating the working connections per hole and altering a sequencing in real time on the basis of connected holes.

[009] These and other objects and advantages of the embodiments herein will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

SUMMARY OF INVENTION [0010] The various embodiments of the present invention provide an electronic system for controlled sequential detonation. The system comprises a plurality of control module(s) and an exploder. The control module comprising an electronic circuit connected to a detonator. The said control module is connected with the said exploder through at least one connector. A predetermined set of the control module(s) and the detonator(s) are arranged in series / parallel where one control module is connected to an adjacent control module creating a serial / parallel detonation. Each control module comprises of an arming circuit, a disarming circuit, a latching relay, a capacitor charging circuit, a capacitor discharging circuit, a power capacitor, an activation circuit consisting of an opto-coupler, an input circuit consisting of an opto- coupler, a programmable microcontroller with crystal oscillator as a clock, a first pulse generator, a second pulse generator configured for sending coded message to the said exploder and a firing circuit with silicon controller rectifier.

[0011] According to one embodiment of the present invention, the said input circuit comprises of at least three ports, where at least two ports of the input circuit are connected to the arming circuit and the disarming circuit respectively and are further connected to the latching relay. The third port is connected to the input of the microcontroller for receiving signals from adjacent control module.

[0012] According to one embodiment of the present invention, the said activation circuit is further connected to the programmable microcontroller, where the activation circuit power ups (trigger) the micro controller when it receives a signal.

[0013] According to one embodiment of the present invention, the said first pulse generator provides a signalling connection between the microcontroller and the exploder. The second pulse generator provides a pre-fire and fire signalling through a connection between the adjacent microcontrollers present in adjacently placed control modules. The first pulse generator and the second pulse generator are also connected with each other.

[0014] According to one embodiment of the present invention, the said one latching relay is activated by the arming circuit leading to charging of the said power capacitor to a predetermined threshold value of current.

[0015] According to one embodiment of the present invention, the said plurality of control module(s) operates in a pre-fire mode and a fire mode.

[0016] According to one embodiment of the present invention, said control module receives a pre fire signal either from the exploder or from an adjacent serially connected control module. The threshold voltage of the said power capacitor is checked / verified by the microcontroller and under condition that the power capacitor exceeds the threshold voltage, the second pulse generator is initiated for sending a coded message to the exploder. The said first pulse generator is activated for generation of the pre-fire command to an adjacent control module after a predetermined programmed delay through the microcontroller. The control module is configured to generate an activation signal and pre final signal after activation of the first pulse generator through an output 2 to be read by an adjacent control module.

[0017] According to one embodiment of the present invention, under condition that any control module receives a fire signal from the exploder or an adjacent control module. Then, the threshold voltage of the said power capacitor by the said microcontroller is verified. The threshold voltage in fire mode is higher than the threshold voltage in a pre-fire mode. In case of fire mode, the said first pulse generator of the first control module is activated for generation of a first fire command (output 1) to an adjacent control module after a predetermined programmed delay (Dl) through the microcontroller of first control module. The adjacent control module generates a repetitive activation signal and fire signal after activation of the first pulse generator through a command (output 2) to be read by an adjacent control module. The firing circuit is activated to detonate the detonator by releasing all the energy of the power capacitor thorough an (output 4) and (output 5) after programmed delay D2, wherein the delay D2 is greater than the delay Dl.

According to one embodiment of the present invention, in case of test mode, the said first pulse generator of the first control module is activated for generation of a first command (output 1) to an adjacent control module after a predetermined programmed delay (Dl) through the microcontroller of first control module. The adjacent control module generates a repetitive activation signal and pre-final signal after activation of the first pulse generator through same command (output 1) to be read by an adjacent control module. The firing circuit remains de activated as the power capacitor does not exceeds the threshold voltage. The output 3 is activated in trial mode which generates an encoded signal which will be read by the master controller/ exploder.

[0018] According to one embodiment of the present invention, the arming circuit provides a high voltage encoded analog signal for charge the power capacitor between 1 microfarad to 10 microfarad at voltages of 130 V - 160 V and a current of 100 milliamps.

[0019] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS [0020] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:

[0021] FIG. 1 illustrates a block diagram for a system for controlled sequential detonation, according to one embodiment of the present invention.

[0022] FIG. 2 illustrates a circuit diagram of the electronic detonation system for controlled detonation, according to one embodiment of the present invention.

DETAILED DESCRIPTION OF INVENTION

[0023] In the following detailed description, a reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. The embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.

DEFINITION(S)

• Activation signal: - A signal that can activates the power source for the microcontroller. After receiving this signal the micro controller boots up

• Pre-final signal - Signal received by the micro controller which instructs the micro controller to generate an encoded signal which can be read by the exploder(this encoded signal is used to verify that the control modules are correctly connected in the field)

• Fire Signal:- Signal received by the micro controller which instructs the micro controller to enable the firing circuit to initiate the detonator • NOTE: Always first the activation signal is generated and then only fire or pre-final signal is generated.

• Arming circuit 201 - Function to operate the latching relay (on state) 203 on receiving a particular signal from the exploder/ master controller.

• Disarming circuit 202, - Function to operate the latching relay (off state) 203 on receiving a particular signal from the exploder/ master controller.

• Latching relay 203, - a bistable electro-mechanical switch

• Capacitor charging circuit 207, - to charge the capacitor within in a particular time and restrict the current to a maximum value.

• Capacitor discharging circuit 204, - to discharge the capacitor if no input signal is received within a particular time frame

• Power capacitor 210, - a capacitor to hold the energy required for operation of the control module and firing of the detonator.

• Activation circuit with opto-coupler 206, - activation circuit on receiving an input trigger signal will activate the power supply for the micro controller

• Input circuit with opto-coupler 205, - the input circuit on receiving an input signal will relay that signal to the micro controller

• Programmable microcontroller with crystal oscillator as a clock 209, -self-explanatory (standard)

• First pulse generator 208, - this consists of transistors which on receiving signal from the micro controller generate pulses to give activation signal , pre-final, fire signal to the adjacent controller

• Second pulse generator for coded message sent to the exploder 211 - consists of high speed transistors which on receiving signal from microcontroller generate the unique id which can be read by the exploder/ master controller.

• Firing circuit with silicon controlled rectifier (SCR)212 - a firing circuit which have multiple scr. On receiving signal from microcontroller the SCR’s activate and allow the complete energy of capacitor to discharge through the detonator

[0024] FIG. 1 illustrates a block diagram for a system for controlled sequential detonation, according to one embodiment of the present invention. With respect to FIG. 1, the system comprises a control module 101 and an exploder 102. The control module 101 comprising an electronic circuit connected to a detonator 103. The exploder 102 is connected to at least one control module 101 through at least one connector 104. A predetermined set of the control module 101 and the detonator 103 are arranged in series and one control module is connected to an adjacent control module creating a serial detonation. Each control module 101 activates the adjacent attached control module(s) after a preset/ programmable delay time. Each control module 101 releases an electrical energy after a preset/ programmable time to fire an instantaneous detonator 103 after activation signal received by an adjacent module or the exploder 102.

[0025] As shown in FIG. 2, the control module 101 comprises an arming circuit 201, a disarming circuit 202, a latching relay 203, a capacitor charging circuit 207, a capacitor discharging circuit 204, a power capacitor 210, an activation circuit with opto-coupler 206, an input circuit with opto-coupler 205, a programmable microcontroller with crystal oscillator as a clock 209, a first pulse generator 208, a second pulse generator for coded message sent to the exploder 211 and a firing circuit with silicon controller rectifier 212.The input circuit 205 has atleast one optocoupler. The input circuit is connected to the input port of the microcontroller. ???. The control module has at least 3 inputs and 5 outputs. The inputs of the control module are connected to the at least 3 outputs of adjacent control module or exploder. The remaining 2 outputs are connected to the instantaneous detonator. A power for the control module is a high voltage capacitor of rated voltage greater than lOOv. The control module needs to be armed before any charging of the power capacitor can take place. An arming is done by operating a electro mechanical bistable switch 203. The Bistable switch 203 is designed in such a way that it operates at low currents of 100 micro amps and high voltage of 100-150v. The bistable switch is operated in arming direction by providing an encoded signal for not more than 1 second. The bistable switch 203 can be disarmed after arming by providing an encoded signal for not more than 1 second.

The activation circuit 206 is further connected to the programmable microcontroller 209. The activation circuit power ups the micro controller after receiving a signal

[0026] The control module operates in 2 modes - pre fire mode and fire mode.

Microcontroller will have minimum 3 outputs and one input.

1) Input - The input signal is received at the microcontroller which activate the microcontroller for - whether the microcontroller has to trigger the detonator (fire signal) or it is a test signal (pre-final)

2) Output 1 - The output 1 is configured to trigger the adjacent control module/modules. This will also specify whether the adjacent module/ modules have to operate in detonator triggering mode or test mode.

3) Output 2 - The output2 is configured to trigger the detonator firing circuit

4) Output 3 - The output3 is configured as trial mode - This will generate an encoded signal which will be read by the master controller/ exploder.

[0027] Pre fire Mode:

[0028] The pre fire mode is used to check the electrical connections before starting the firing sequence. In pre fire mode, the power capacitor 210 is charged between 30v to 45v which is not enough to fire the detonator 203. After receiving the pre fire signal from an adjacent control module or the exploder, the control module generates a coded signal to be read by the exploder. Then after a certain delay, the control module sends the pre fire signal to the adjacent control module and the process continues till the end of the series (formed by the connection of the control module). The exploder reads the signals and calculate the number of control module attached in the total circuit and if there is a fault, then the number of the control module till the connection is intact is displayed so that the user can correct the circuit at that point.

[0029] In a case where the inputs of multiple control modules are attached to an output of a single control module. Then, the exploder is able to read the multiple control module attached by using multiplexing technology.

[0030] Fire Mode:

[0031] After all pre-firing checks are done, the exploder initiates the firing sequence. Firstly, the charge the power capacitors to high voltage 100- 150V. When the power capacitors of all connected control modules charge to the desired voltage, the exploder gives the firing signal to the closest control module. This control module after a certain delay D1 gives the firing signal to the adjacent control module and after a certain delay D2 initiates the attached detonator (D2>D1).

[0032] According to one embodiment of the present invention, the arming circuit consists of high voltage silicon transistors, inductors, capacitors. The arrangement if the arming circuit is in such a way that only a high voltage encoded analog signal can charge a secondary capacitor between 1 micro farad to 10 micro farad to voltages of 130 v - 160 v. After this encoded signal stops this capacitor discharges its energy in the coil of the latching relay hence activating the relay. The current used for charging this secondary capacitor is less than 100 micro amps for less than 1 second.

[0033] According to one embodiment of the present invention, the disarming circuit is similar to the arming circuit. The secondary capacitor discharges in the opposite direction hence deactivating the relay. After disarming the exploder can check whether all EMs have been successfully disarmed and inform the user of the same. [0034] According to one embodiment of the present invention, the latching relay can be a single coil SPST/SPDT (SINGLE POLE SINGLE THROW/ DOUBLE THROW) latching relay with coil operating voltage of more than lOOv which can bare substantial shock and vibrations. Miniature version to be inserted inside the detonator shell can be made using MEMS manufacturing technique. The latching relay 2 is a SPDT configuration, when disarmed it shorts OUTPUT 4 AND 5 so that detonator cannot be initiated accidentally.

[0035] According to one embodiment of the present invention, capacitor charging circuit consists of a current controlled source consisting of one PNP transistor. This also consists of 3 silicon switches activates only when a continuous dc current is applied and shuts down when any ac or intermittent dc current is applied. Also, it protects the capacitor from charging to higher voltages than for which the capacitor is rated.

[0036] According to one embodiment of the present invention, the capacitor discharging circuit consists of at least four silicon switches and capacitors with resistors. After the charging current stops (that is the exploder stops the charging process) and no activation input is received for some duration the power capacitor discharges automatically.

[0037] According to one embodiment of the present invention, power capacitor is a 10 microfarad-330 microfarad, 100-150v rated polar capacitor to power the entire EM and it also stores the energy for firing the detonator

[0038] According to one embodiment of the present invention, the activation circuit consists of an optocoupler and 2 silicon-controlled rectifiers (SCR) . The optical led is excited from the input received by input 2. The transistor end is connected to the power capacitor which activates when the led is activated. This in turn activates SCR attached to the power capacitor and boots up the microcontroller.

[0039] According to one embodiment of the present invention, the input circuit consists of an optocoupler attached to the input of the microcontroller. When the optocoupler receives a signal from input 2, it activates the input of the microcontroller for the duration of the signal.

[0040] According to one embodiment of the present invention, the programmable microcontroller is a 8-bit programmable microcontroller with an external crystal oscillator clock with precision lOppm.

[0041] According to one embodiment of the present invention, the pulse generator for activation and fire or pre fire command to other control module. The pulse generator consists of at least three semiconductor switches. The pulse generator are capable of generating high frequency pulses in MHz.

[0042] According to one embodiment of the present invention, the pulse generator for sending coded message consist of at least two semiconductor switches and a highly accurate Zener diode. The pulse generator generates a constant voltage coded signals when input is received from microcontroller.

[0043] According to one embodiment of the present invention, the firing circuit with consists of at least two SCRs and a voltage detection device (consisting of MOSFETS, activates only when power capacitor is at a certain minimum voltage). The SCRs activates when it receives signal from microcontroller and voltage detection device. The SCRs dissipates all the energy of the power capacitor into the detonator.

[0044] The safety features in the control module is as follows: a) Automatic discharging of the power capacitor; b) If after charging no signal is received by the control module for some duration it will automatically discharge the power capacitor; c) The control module can be disarmed anytime before giving the firing signal; d) The control module is shielded from any electromagnetic radiations by use of metal housing as a faraday cage; e) The power capacitor can only be charge by a DC current; f) No AC or high frequency current can charge the capacitor; g) Firing and pre firing signals are digital encoded signals which are not susceptible to noise and stray currents; h) The control module has a voltage limiting diode which activates if the inputs or outputs are subjected to voltages of more than 200v and hence prevents any damages due to over voltage.

Working Example

[0045] Before the entire circuit (consisting of multiple control modules) is triggered it will be tested to check whether all the connections have been done properly. In the testing phase the power capacitor will be charged to a low voltage which cannot trigger the detonator. When the master controller gives a testing signal to the 1st control module the 1st control module sends an encoded signal back to the master controller. The encoded signal will have a unique (each micro controller will carry a unique key) 16 digit numeric key. This signal will have a start and a stop bit. This key will have a transmission frequency between 100 kHz to 10 MHz. This signal the master controller will read and record. After sending this encoded signal to the controller and after a programmable delay of (X millisec) the first controller will send a testing signal to the second controller and this process will go on. After all the control units have sent their unique key to the exploder (master controller) . The master controller will display the total number of control modules in the circuit. If the user finds that the total number of control modules is ok he will then start the firing sequence. ADVANTAGES OF THE INVENTION

[0045] The present detonation system has delay time accuracy of the electronic system of +/- 0.1%, does not use a shock tube and has no detonating or hazardous or sound producing components on the surface. Also, the present system avoids a non- optimal detonation by calculating and alerting about a number of connected control modules. The present system is modular and cost effective in nature with least complex assembly.

[0046] Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration by way of examples and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

Claims

CLAIMS:

1. An electronic system for controlled sequential detonation comprising: a plurality of control module(s), wherein each control module comprises of an electronic circuit connected to a detonator; and an exploder, wherein the exploder is connected to at least one control module through at least one connector; wherein, a plurality of set, each including said control module and the detonator, arranged in series/ parallel such that one control module is connected to an adjacent control module in series/ parallel or combination of series and parallel creating a serial detonation.

2. The system as claimed in claim 1, wherein each control module comprises of an arming circuit, a disarming circuit, a latching relay, a capacitor charging circuit, a capacitor discharging circuit, a power capacitor, an activation circuit consisting of an opto-coupler, an input circuit consisting of an opto-coupler, a programmable microcontroller with crystal oscillator as a clock, a first pulse generator, a second pulse generator configured for sending coded message to the exploder and a firing circuit with silicon controller rectifier.

3. The system as claimed in claim 2, wherein the said input circuit comprises of at least three ports, where at least two ports of the input circuit are connected to the arming circuit and the disarming circuit respectively and are further connected to the latching relay.

4. The system as claimed in claim 2, wherein the said activation circuit power up / trigger the programmable microcontroller when the activation circuit receives an encoded signal through the input port.

5. The system as claimed in claim 2, wherein the first pulse generator provides a signalling connection between the microcontroller and the exploder; and wherein the second pulse generator provides a pre-fire (test) and fire signalling through a connection between adjacent microcontrollers present in adjacently placed control modules; and wherein the first pulse generator and the second pulse generator are connected with each other.

6. The system as claimed in claim 2, wherein the said firing circuit provides a signalling connection between the microcontroller of a control module and the connected detonator.

7. The system as claimed in claim 3, wherein the said latching relay is activated by the arming circuit leading to charging of the power capacitor to a predetermined threshold value of current.

8. The system as claimed in claim 1, wherein the control module is configured to operate in a pre-fire (test) mode and a fire mode.

9. The system as claimed in claim 2, wherein the said arming circuit activates charging of the power capacitor between 1 microfarad to 10 microfarad at voltages of 130 V - 160 V and a current of 100 milliamps only after a high voltage encoded analog signal of more the 150V is received by the arming circuit.

10. The process for controlled sequential detonation during a pre-fire (test) mode comprises the steps of: receiving a pre fire (test) signal from the exploder or an adjacent serial connected control module; checking the threshold voltage of the power capacitor by the microcontroller; initiating the second pulse generator for sending a coded message to the exploder; activating the first pulse generator for generation of the pre-fire command to an adjacent control module after a predetermined programmed delay through the microcontroller; wherein, the said control module is configured to generate an activation signal and pre-final signal after activation of the first pulse generator through an output (2) to be read by an adjacent control module.

11. The process for controlled sequential detonation during a fire mode comprises the steps of: receiving a fire signal from the exploder or an adjacent control module ; checking a threshold voltage of the said power capacitor by the said microcontroller, wherein under condition that the threshold voltage in fire mode is higher than the threshold voltage in a pre-fire test mode; activating the first pulse generator of the first control module for generation of a fire command to an adjacent control module after a predetermined programmed delay D1 through the microcontrollerof the first control module; wherein, the adjacent control module generates a repetitive n activation signal and fire signal after activation of the first pulse generator through a command output 2 to be read by an adjacent control module; activating the firing circuit to detonate the detonator by releasing all the energy of the power capacitor thorough an output 4 and output 5 after programmed delay D2, wherein the delay D2 is greater than the delay Dl .