JPS6353480B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detonator circuit for detonating an electric detonator having an electric time delay device, and is particularly intended to enable a large number of detonators to be detonated simultaneously and to obtain high timing accuracy.

Japanese Patent Publication No. 48-23887 is known as an electric detonator having an electric time delay device. Although this electric time delay device is constructed of a time delay circuit consisting of a resistor and a capacitor, it is not practical as an electric detonator. In other words, it was found that it was difficult to fire multiple blasts at once using this method, and accurate timing accuracy could not be obtained, so it was found to be impractical for actual blasting. However, the number of electric detonators used for normal blasting is generally several dozen for both open blasting and tunnel blasting.

In order to overcome these drawbacks, an electric detonator with an electric time delay device has been proposed in Japanese Patent Application Laid-open No. 43454/1983. This is an energy storage capacitor installed in parallel between the two power supply lines (receiving lines) of the electric detonator, so that when multiple simultaneous fires are to be fired in series, energy is first supplied from the power supply circuit. By storing energy in a capacitor, it is possible to completely detonate even if the supply of blasting energy is interrupted due to blasting impact.

It has been found that the use of conventional detonators to detonate such electrical time-delaying caps is particularly problematic. In other words, in conventional blasters, when a predetermined voltage is applied to a large number of electrically delayed electric detonators, if one electric detonator is detonated before the application time, the power supply circuit is electrically connected to the electric detonator, and the electric detonator is connected to the electric detonator. It was found that accurate seconds could not be obtained because the applied voltage varied.

This will be explained with reference to FIG.
Both ends of the capacitor 11 are selectively connected to a DC power supply 13 or a pair of output terminals 14 and 15 by a switch 12. A plurality of electrical delay detonators 16 are connected in series between the output terminals 14 and 15. An energy storage capacitor 17 is connected between a pair of feed lines of each electrical delay electric detonator 16 .
A resistor 18 is connected between the output terminals 14 and 15 to prevent the output terminals from becoming open.

Each electric detonator 16 is, for example, as shown in FIG.
An energy storage capacitor 17 is connected between the power supply lines 21 and 22, and a time delay circuit 23 is connected in parallel with the capacitor 17. After a predetermined period of time after power is applied to the delay circuit 23, the output turns on the electric switch 24, and the electric charge stored in the capacitor 17 is supplied to the ignition resistance wire 25 through the switch 24, which generates heat. , the explosive portion 26 is ignited and exploded via the ignition ball attached to the resistance wire 25.

In FIG. 1, when the switch 12 is switched from the power supply 13 to the output terminals 14 and 15, the energy stored in the capacitor 11 charges each capacitor 17 of each electric detonator 16. This activates the delay circuit 23 in each electric detonator 16 to cause it to explode as described above. If one electric detonator detonates while each electric detonator 16 is being supplied with energy from a power source, in this example a capacitor 11, the voltage applied to the other energy storage capacitors 17 changes. In other words, since the ignition resistance wire 25 has a small resistance of, for example, about 1 Ω, when the switch 24 is turned on, the resistance value at both ends of the electric detonator becomes extremely small, resulting in a state almost like a short circuit. Therefore, the voltage across the capacitor 11 is Va, and the number of detonators 16 is n.
In this case, a voltage of Va/n is applied to each energy storage capacitor 17 before the explosion. The delay circuit 23 operates with this voltage. However, when the switch 24 of one electric detonator is turned on, a voltage of Va/(n-1) is applied to the capacitor 17 of the other electric detonator. Since the applied voltage changes in this way, the time delay of the time delay circuit 23 changes and the correct time delay cannot be obtained.

The object of the present invention is to provide a correct delay time when detonating electrically delayed electric detonators even if one electric detonator is detonated first.

According to the present invention, a cutoff circuit is provided which cuts off the voltage applied to the electric detonator group after a certain period of time has elapsed since the start of supplying energy to the electric delay electric detonator group. In this case, in the electric delay electric detonator,
Activate the cutoff circuit before the electric detonator, which ignites first. This cut-off circuit may be mechanical or electrical, but electrical is preferred from the viewpoint of quick switching response. For example, there are switching elements such as relays and thyristors, and among them, mercury contact relays are preferred.

The electric detonator in the detonator circuit can be connected in series, in parallel, or in series-parallel, but among these, the method of serial connection is often used, and the effects of the present invention are particularly obtained in this case. Furthermore, since the electric detonator can fire a large number of detonators at the same time, an energy storage capacitor is always required, and it can be seen that if the present invention is applied to these cases, the accuracy of the time can be improved.

There are various ways to cut off the applied voltage after a certain period of time after starting the supply of energy to the electric detonator, such as a CR time constant, a digital timer, and a spring-type mechanical method. The following example uses a delay circuit configured with a capacitor and a resistor.

FIG. 3 shows a detonator circuit according to the present invention, in which parts corresponding to those in FIG. 1 are given the same reference numerals.
In this invention, for example, a normally open contact 27a of a relay 27 is inserted in series between the switch 12 and the output terminal 14. Coil 27b of the relay 27
A resistor 28 is connected between both ends of the power supply 32, and a power supply 32 is connected through a capacitor 29 and a switch 31. Switch 31 is switch 12
It is preferable that the switch be turned on in conjunction with switching from the power source 13 to the relay 27 side. Due to the time constants of the coil 27b, resistor 28 and capacitor 29, the contact 27 is turned on after the switch 31 is turned on.
Set the time that a is on. In other words, this time is selected to supply sufficient energy to each capacitor 17 of the electric detonator 16, but to be smaller than the duration of the electric detonator 16 which detonates earliest.

In this configuration, when switch 12 is switched to the relay 27 side and switch 31 is turned on (or after switching switch 12, switch 31 is turned on).
), the relay contact 27a is connected to the coil 2
7b, the resistor 28, and the capacitor 29 are turned on for a certain period of time, and through this, energy is supplied to the capacitor 17 of each electric detonator 16. However, before any one of the electric detonators 16 explodes, the relay contact 27a is turned off, ie, the power applied to the electric detonators 16 is cut off.

FIG. 4 shows another embodiment of the invention, in which the power source 1
Both ends of 3 are connected between the anode and cathode of a thyristor 34 through a switch 12 and a resistor 33. A series circuit of resistors 35 and 36 is connected between the anode and cathode of the thyristor 33, as well as a series circuit of a resistor 37 and a capacitor 38. In addition, a diode 39 is connected between the anode and cathode of the thyristor 33, and the output terminal 14,
15 are connected. Resistor 37 and capacitor 3
a programmable union transistor between the connection point of 8 and the gate of thyristor 34;
The anode and cathode of so-called PUT 41 are connected, and the gate of PUT 41 is connected to the connection point of resistors 35 and 36.

When the switch 12 is turned on, the switch 12
The power of the power supply 13 is further supplied to the electric detonator 16 through the diode 39 . At the same time, the capacitor 38 is gradually charged, and for a predetermined period of time,
That is, after supplying sufficient energy to each capacitor 17 and before the earliest explosion of the electric detonator 16, the PUT 41 is turned on, and accordingly the thyristor 34 conducts, from the power supply 13 to the electric detonator 16. The power supply will be cut off.

Examples of the invention will be described below.

Example 1 The power supply 13 is activated using the detonation circuit shown in Fig. 3.
250V, switch 12 is a micro switch, and capacitor 11 is 10μF (WV300V, M.
P. capacitor), a mercury contact relay is used for the relay 27, and the power supply 37 for the relay is
The operating time of the relay 27 is set to 10 milliseconds using a 5V DC power supply, a 500Ω resistor 28, a 25μF delay capacitor 29, and an 800Ω resistance of the coil 27b, and 20 electrical delay detonators 16 are connected in series. was successfully and accurately detonated.

Example 2 The circuit shown in Figure 4 was used as the detonator circuit, the DC power supply 13 was 100V, the switch 12 was a micro switch, and the delay capacitor 38 was
Using 0.01μF and 1MΩ for the delay resistor 37, the operating time was set to 10 milliseconds, and this drove the thyristor 34. Ten electrical delay detonators 16 were connected in series, and firing was accurate. The time was obtained.

As can be seen from the above embodiments, according to the present invention, by providing a circuit that cuts off the power supply at a predetermined time after startup, the electrically delayed electric detonator can be detonated with higher precision in seconds.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a conventional blaster, FIG. 2 is a block diagram showing an electrical delay detonator, and FIG. 3 is a circuit diagram showing an example of a detonating circuit according to the present invention.
FIG. 4 is a circuit diagram showing another embodiment of the invention. 11: capacitor, 12: switch, 13: DC power supply, 14, 15: output terminal, 17: energy storage capacitor, 16: electrical delay electric detonator, 23: delay circuit, 24: switch, 25: ignition resistance wire, 26: Explosives Department, 27: Relay, 31:
Relay switch, 32: Relay power supply, 29: Time delay capacitor, 34: Thyristor, 39: Backflow prevention diode, 41: PUT.

Claims (1)

[Claims] 1. In a detonation circuit that detonates a plurality of electrically delayed electric detonators from a common power source, a cutoff circuit that interrupts voltage applied from the power source to the group of electric detonators;
A detonator circuit for an electric detonator, comprising: a drive circuit that brings the cutoff circuit into a cutoff state after a predetermined time from the start of voltage application from the power supply to the group of electric detonators.