Delay circuit for electric blasting, detonating primer having delay circuit and system for electrically blasting detonating primers

摘要

A delay type electric detonating primer for use in a multiple-step blasting system including a capacitor (2) for storing electric changes supplied from an electric blaster (10) via bus wires (8a, 8b) and leg wires (9a, 9b), an actuation circuit (3) connected across the capacitor (2) for generating an actuation signal when an energy supply from the electric blaster is stopped, a clock pulse generating circuit (4) having a crystal oscillator (20) and being energized with energy stored in the capacitor (2) to produce clock pulses, a counting circuit (5) which is initiated to count the clock pulses in response to the actuation signal, and generates an ignition signal when the counter has counted the predetermined number of clock pulses, and a switching circuit (6) for discharging electric charges stored in the capacitor through an igniting resistor (27) in response to the ignition signal.