JPH0692879B2 - Blaster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used for an electromagnetic induction detonation system in which, for example, a blast bus and an electric detonator having a shorted bridge are electromagnetically connected by a transformer. Related to the blaster.

[Prior Art] An electromagnetic induction detonation system has a blaster 1 as shown in FIG.
2 connected to the bus and the shorted leg 4 of the electric detonator 3.
Are electromagnetically coupled with the transformer core 5, and a high-frequency alternating current is passed from the blasting device 1 to the circuit.
The electric detonator 3 is detonated through the electric detonator for the purpose of improving the safety of the electric blasting work and saving labor.

Figure 2 shows a detailed view of the connecting part in the system. This connecting part consists of a magnetic closed circuit formed by transformer cores 6 and 7, and a busbar 2 and a shorted leg 4 of an electric detonator 3. In this case, there is no concern about static electricity or stray current because the detonator portion is in a completely short-circuited state.

However, in such a system, since the induced current by the transformer core is used, the energy loss due to the characteristics of the transformer core must be taken into consideration particularly. Therefore, in order to efficiently perform electromagnetic induction blasting, a high voltage is required. , Instantaneous blast circuit of high frequency high frequency current (connecting part)
A blaster capable of supplying to For this reason,
The blaster used in this system first converts direct current from a low-voltage power source such as a dry battery to alternating current, boosts it, stores it in a blast capacitor, and then instantly converts its electrical energy to high frequency at the time of blast. At the same time, it must be supplied to the blast circuit as blast power.

As a method for high frequency conversion, conventionally, for example, as described in Japanese Patent Publication No. 38-22915 shown in FIG. 3, the electric charge stored in the blasting capacitor 9 from the power supply section 8 is discharged by the switch 10. There is a method of causing transient vibration by the inductance L of the capacitor 9 and the coil (core) 11.

Further, the one described in Japanese Examined Patent Publication No. Sho 22-22608 shown in FIG. 4 has a unidirectional circuit in which the trigger circuit 14 closes the silicon controlled rectifier 13 while the blast capacitor 9 stores electric charges. It has a structure in which a large pulsed current flows and an induced voltage is generated on the side of the detonator 3 with the core 15 interposed therebetween. In addition, the literature [Explosives and Security, 16.5 (198
4)] also reported a blasting device using the self-excited oscillation method.

[Problems to be Solved by the Invention] In general, it is difficult to convert a discharge current into a high frequency because it is a large current and is transient, and similarly, each of the above methods includes various problems. .

For example, in the method shown in FIG. 3, when transient vibration is caused by the CL circuit, in order to obtain an optimum frequency, it is necessary to obtain from various combinations of the capacitor C and the inductance L, and the variation of the inductance L is caused. Therefore, there is a drawback that the vibration state becomes unstable and only inefficient blasting can be performed. Furthermore, considering that it is very difficult to manufacture a transformer having a constant inductance L, this method is not practical at all.

Further, in the method shown in FIG. 4, since only one unidirectional pulse wave is passed, the electric energy required for ignition is applied to the electric detonator 3 side via the core 15 by this one unidirectional pulse current. In order to achieve this, a large and expensive low-frequency core must be used, and if a high-frequency ferrite core is used instead of this low-frequency core, the power transfer efficiency becomes extremely poor. Being prepared for this, the blaster output capacity must be set to a large capacity that cannot be considered by common sense, and it is completely unsuitable for practical use.

Further, the self-excited oscillation type blaster is easily affected by the load of the blasting circuit. Therefore, the oscillation period and the on / off ratio greatly change depending on the bus length, the detonator leg length and the number of detonators, and There is a problem that the transmission efficiency is deteriorated based on the frequency characteristic and that the oscillation is stopped depending on the load.

[Means for Solving the Problem] The inventors of the present invention have conducted various experiments and studies in order to solve the problems of the blaster in the above situation, and as a result, found that It has been found that a blaster without the above-mentioned problems can be obtained by separately providing a semiconductor drive oscillating section and by arranging the oscillating section stably and not receiving interference from the switching section at all. completed.

That is, the blasting device of the present invention has a DC-D
The C converter 16 converts low-voltage direct current (for example, from a dry cell) into alternating current, boosts it, further rectifies it, and stores the obtained high-voltage direct current from the converter 16 in the blasting capacitor 17 through the blasting switch 21. It is composed of a unit 22, a high frequency conversion unit 24 for converting the discharge current of the blasting capacitor 17 obtained through the blasting switch 21 into a high frequency by switching, and a high frequency signal generation unit 23 for performing the switching operation, which is stable. A high-frequency transient large current indicating the oscillation state can be obtained at the output section 20. Output section 20
For example, a bus bar 2 forming a blasting circuit as shown in FIG. 1 is connected to this.

The high frequency signal generator 23 has a semiconductor drive oscillator 19, and the high frequency converter 24 has a switching unit 18.

Since the switching high-frequency conversion method only turns on and off the DC voltage, it can perform high-frequency conversion with high efficiency in terms of power and voltage, unlike the case of sine wave conversion, and the conversion semiconductor has a small capacity, small size, and It has various advantages such as being inexpensive. Further, if the switching unit 18 of the high frequency conversion unit 24 has a push-bull output configuration, a high voltage output is possible, and it is possible to cope with a circuit with a high load such as when the blasting busbar and the leg are long.

Further, the high-frequency signal generator 23 has a CR oscillator circuit driven by a C-MOS IC, and this CR oscillator circuit has a much more stable oscillation state than a CL circuit, and can be downsized and inexpensive. The advantage is that Further, the generating unit 23, a stable circuit consisting of a Zener diode and a resistor that can always supply a constant constant voltage to the CR oscillation circuit from the transient current from the blasting capacitor 17, and further, the generating unit 23 switches. Part 18
The oscillation unit should not be interfered with by the load fluctuation from the side.
An interface circuit composed of a C-MOS IC is incorporated between the switch 19 and the switching unit 18.

Therefore, since the semiconductor-driven CR oscillation circuit that sends a signal to the switching unit 18 is not affected by the load of the blast circuit, stable oscillation is not affected by the bus length, the leg length of the electric detonator, or the number of detonators. Indicates the status.

At the actual blasting site, the blasting bus bar is at least 100m.
~ 200m is required. Generally, when the frequency is high, the power and the voltage loss due to the increase in impedance increase, and the designer must be prepared for this and apply a large voltage to the output section. Therefore, from the viewpoint of impedance, it is better that the oscillation frequency is lower, but considering the balance with the energy transfer efficiency characteristics of the ferrite core,
Approximately 10kHz to 80kHz is suitable.

Examples of the semiconductor switching element used in the present invention include a bipolar power transistor and a power MOSF.
There are ET, etc., and especially power MOSFETs are suitable for use because they are excellent in miniaturization, resistant to transient phenomena, and inexpensive.

[Examples] The present invention will be described below with reference to Examples.

Using a dry battery and a DC-DC converter 16, boost the voltage to about 300 V to make a charging unit 22, a blasting capacitor 17 is a 400 μF electrolytic capacitor, and a stabilizing circuit of an oscillating unit 19 in the generating unit 23 is
A Zener diode and a resistor were used, and the same C-MOS IC as the oscillator circuit in the generator 23 was used for the interface. Further, a power MOSFET having high withstand voltage and withstand current is used for the switching unit 18.

Using the blasting device of the present invention having the above-mentioned specifications, the blasting busbar length is 50 m to 300 m, the leg length of the electric detonator is 1.5 m to 4.5 m, and the number of the detonators to be blasted is 5 to 200. Under the conditions, when the output waveform was observed with a synchroscope in the frequency range of 10 kHz to 100 kHz, it was confirmed that there was no change in the oscillation period, waveform, etc., and that a stable high-frequency wave could be obtained. Ignition tests were carried out using electric detonators with a long wire length, and it was confirmed that at least 100 or more practically completed explosions were completed.

[Effects of the Invention] As described above, according to the present invention, a stable oscillation state is exhibited without being influenced by the load on the blasting circuit side, a small size, a low cost, and a practical number of blasting are practical. Blaster can be provided.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an electromagnetic induction detonation system, FIG. 2 is a detailed diagram of a connecting portion that is electromagnetically coupled by a transformer core, and FIG. 3 is a blaster circuit diagram described in Japanese Examined Patent Publication No. 38-22915. FIG. 5 is a circuit diagram of a blaster described in Japanese Patent Publication No. Sho 22-22608, and FIG. 5 is a diagram showing an example of a blaster circuit diagram of the present invention, which is a single high-frequency conversion output circuit configuration. DESCRIPTION OF SYMBOLS 1 ... Explosion device, 2 ... Bus bar, 3 ... Electric detonator, 4 ... Shorted leg wire, 5 ... Coupler, 6 ... I-type transformer core, 7 ... U-type transformer core, 8 ... Power supply part using vibrator converter , 9 ... Blasting capacitor, 10 ... Switch, 11 ... Coil, 12 ... Power supply part, 13 ... Silicon controlled rectifier, 14 ... Trigger circuit, 15 ... Toroidal core, 16 ... DC-DC converter, 17 ... Blasting capacitor, 18 ... Semiconductor A switching section using a switching element, 19 ... Stabilized high frequency oscillation circuit, 20 ... Output section, 21 ... Blasting switch, 22 ... High voltage generating charging section, 23 ... High frequency signal generating section, 24 ... High frequency converting section.

Claims (3)

[Claims] 1. A blaster for causing a high-frequency current to flow through a blast bus to detonate an electric detonator electromagnetically coupled to the blast bus, and a switching section having a semiconductor switching element for generating the high-frequency current by switching, An oscillation section including a semiconductor drive CR oscillation type signal generation circuit for generating a signal for causing the switching section to perform a switching drive, wherein the switching section and the oscillation section each form an individual circuit. A blaster characterized by being present. 2. The blasting apparatus according to claim 1, wherein the oscillating unit has means for stabilizing discharge electric energy of the blasting capacitor and using it as a power source element of the signal generating circuit. 3. The semiconductor switching device comprises a power MO
The blasting device according to claim 1, which is an SFET.