SU252135A1 - Apparatus for electric blasting of charges from the AC network - Google Patents

Description

Portable devices for electrical blasting of charges from an alternating current network with a voltage of 220 V are known that can explode up to 80 parallel-connected electric detonators. In such devices, a gas glitter with an ignition potential of 200 V is connected in series with the explosive circuit, thanks to which, after pressing the pushbutton button, the ignition current is switched on into the explosive circuit when the sinusoid is close to the maximum.

However, the use of a gas discharge device in the device does not exclude the moments of switching on of the current in the area of failures; with a large total current consumed by the explosive circuit from the mains, the device cannot provide a rated current of 1 a per group, since at the moment of switching on the current into the explosive circuit, the voltage on its terminals due to a large voltage drop in the long supply line turn out to be lower than the calculated one, and the voltage in the supply line can only be checked without loading it with a current; The circuit for measuring the resistance of an explosive circuit is not reliable enough.

In the proposed device, in order to increase its reliability and reduce its dimensions, a device for checking the voltage of the supply line under load is installed, connecting to this line when the supply voltage drops below the allowable value, the equivalent resistance through the thyristor, including the test current, and the output of the voltage divider supply line in series with a capacitor, a switching diode, an unlocking, and a resistor. The pulse from the latter in the case of unlocking the switching diode enters the signal and blocking device. To switch the test current to the thyristor with short pulses with relatively large pauses in series with the control electrode, a switching diode, a blocking generator output winding and a capacitor are turned on.

The drawing shows a functional electrical circuit of the device.

In the main circuit, in series with the electric detonator (ED), a silicon controlled thyristor gate 1 of the VKU-10 or VKU-50 type is used, which plays the role of a contactless key. It is unlocked at a given point of the sinusoid by a pulse applied to the control electrode of the thyristor from the control circuit.

The thyristor control circuit contains a power supply unit 2, a phase-shifting bridge 3, an acute-angle pulse shaping device 4, a stand-by blocking generator 5, a thyristor triggering device 6, a device 7 for

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checking the voltage at the terminals of the device during short-term connection of the current to the circuit of equivalent resistance 8, light signaling device and relay 9, contacts 10 of the relay, device 11 for measuring the resistance of the explosive chain, explosive switch 12 (111-114) and device 13 for prohibition signaling the blast.

Switch 12 is controlled by a blasting key. It has three positions:

I - "Measurement of resistance; II - “Check voltage;

III - “Explosion.

The scheme works as follows.

When the switch 12 is set to position I ("Measurement of resistance") and the connecting plug is turned on in the power supply network, the DC voltage from the power supply unit 2 goes to the device 11 to measure the resistance of the explosive circuit and the same value of the equivalent resistance 8 is set at the same time.

The alternating sinusoidal voltage from the node 2, shifted in phase by means of bridge 3 relative to the supply voltage, is transformed into acute-angled pulses.-in device 4. These pulses push the waiting blocking generator 5, which each period is sent at a given fixed point sinusoidal one rectangular pulse into the thyristor triggering device 6. The latter, approximately once every 0.5 sec., Can output a pulse unlocking the thyristor, provided that the switch is in the P position ("Voltage Check). In this case, the phase of the trigger pulse relative to the sinusoid of the current is maintained as determined by the phase-shifting bridge 3.

When switching the switch to position II, approximately 0.5 seconds after closing its contacts, device 6 sends a trigger pulse to the thyristor valve 1, which, when opened, switches the current (via switch PB) to equivalent resistance 8. Since the value of equivalent resistance equal to the resistance of the explosive circuit, the current in the equivalent resistance is the same as it would have been when voltage was applied to the explosive circuit.

When the test current is turned on, the device input voltage is monitored by device 7, which, if this voltage is within the specified limits, sends a pulse to the light signal device and the relay 9. In this case, the signal neon lamp is turned on, and the closed contact 10 of the relay prepares the control circuit of the valve -tiristor to supply the trigger pulse. 252135

When Switching switch 12 to position III (“Explosion) is about 0.5 seconds after closing its contacts, start-up device 6 issues a triggering pulse to thyristor 1, which switches the ignition current into an explosive circuit.

If during the test switch-on of current (in position II of switch 12) the voltage at the input of the device is below the preset limit, the light-signaling device and relay 9 do not operate, and the contact 10 of the relay remains open. At the same time, the neon lamp starts blinking once every 0.5 sec - the device 13 for signaling the prohibition of an explosion.

Due to the use of a powerful semiconductor controlled fan-thyristor, the device allows you to simultaneously blow up to 100 parallel-connected groups of electric detonators. The number of series-connected electric detonators in each group can reach 70 with a network voltage of 220 V and i23 with a voltage of 380 V.

Subject invention

An apparatus for electric detonation of charges from an alternating current network, containing a silicon controlled thyristor valve, a power supply unit, a phase-shifting bridge, a pulse shaping unit, a standby blocking generator, a control unit triggering unit, an equivalent resistance equal to the resistance of the explosive circuit, an alarm and blocking unit, a device for measuring the resistance of an explosive circuit, and an explosive switch, characterized in that, in order to increase the reliability of operation and block the device, reduce its size It contains a device for checking the voltage of the supply line under load, connecting to the supply line when the supply voltage decreases below the allowable value, equivalent resistance through the thyristor, including the test current, and turning on the output of the voltage divider of the supply line in series with a capacitor, a switching diode, unlocking and resistor, the pulse from which, in the case of unlocking the switching diode, enters the signal and blocking devices, and to turn on the thyristor ohm test current short pulses with relatively long pauses in series with its control electrode of the switching diode is included, the output winding of the blocking oscillator and a condenser.

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