CS210865B1 - Electrical system wiring to ensure supply line safety at blasting operations - Google Patents

Abstract

The invention solves the connection of an electrical system to ensure the safety of the supply line during blasting work, namely against the risk of ignition of the surrounding explosive environment and against the introduction of unwanted discharges. The essence of the invention lies in the fact that the power supply is connected to a high-frequency oscillator, at the output of which there is a transformer, connected by its output to a rectifier, to the output of which a limiter is connected, connected via a central conductor, the first conductor and or the second conductor both with the supply line and with the evaluation unit, to the output of which a signaling part is connected, a blocking circuit can be connected to the output of the signaling part, to the output of which a detonator is connected.

Description

The invention solves the connection of the electrical system to achieve the safety of the supply line during blasting operations against the danger of ignition of the surrounding explosive environment and before the introduction of undesirable leakages.

In explosive areas, the issue of explosion safety is becoming increasingly important in blasting operations. On the one hand, sufficient electrical energy must be supplied to the diesel circuit in order to reliably detonate charges, but this can also cause a dangerous situation. Although generally applicable safety regulations foresee the measurement of the surrounding atmosphere before launching, a hazard whose threat is particularly acute in harsh working conditions cannot be ruled out at breaks, local concentrations, etc.

Previous blasting work, transport or mechanization mechanisms or transport-damaged supply lines are a common occurrence in practice. The surrounding damp and aggressive environment helps to reduce electrical strength between the conductor wires when damaged. During the firing, electrical discharges occur at damaged points of the line. Experiments have shown that electrical sparking of this kind reliably ignites an explosive mixture even when the supply line is connected to the nominal load.

In addition, unwanted leakage may occur and cannot be routinely provided by the measuring instruments used. These unwanted leakage leads reduce the value of the electrical impulse needed to ignite the electrical network, and thus also lead to time failures with other economic loss consequences.

The current practice is not satisfactory. Only the continuity of the ignition circuit and the visual inspection of the lines are performed. Given the nature of the operation, the operations performed are not a sufficient guarantee of safety.

These drawbacks are eliminated by wiring the electrical system to achieve safety of the supply line against the risk of ignition of the surrounding explosive atmosphere and avoiding unwanted leakage according to the invention, which is based on the fact that the power supply is connected to a high frequency oscillator. a rectifier, to the output of which a limiter is connected, connected by means of a central conductor, a first conductor and / or a second conductor both to the supply line and to the evaluation unit to which the signaling part is connected to. In the output of the signaling part, a blocking circuit can be connected, at the output of which a differential converter is connected. Eventual defects in the supply line for blasting operations are interconnected by signaling at the gunner, eventual blocking of the blasting unit, which prevents the initiation of the ignition.

Power is supplied to a supply line that uses two insulated conductors disposed in a semiconductor mass, also overlapping the central conductor disposed between the two insulated conductors. When the electrical voltage is applied between the center conductor and one of the insulated conductors, the capacity of the duct circuits is charged.

The required electrical energy is produced in an oscillator powered by the connected power supply. High-frequency electrical oscillations are converted by the transformer to a higher voltage, rectified and current-limited before being switched to the supply line. The evaluation unit, connected to the input of the supply line, monitors the energy conditions in the barbecue circuit. In case of disruption of the ignition line, ie during leakage, short circuit, circuit break, etc., a signaling unit is activated to warn the operator of a dangerous situation. A blocking circuit can be connected to the signaling unit which disables the spit in the event of an emergency.

The use of current and voltage limitations in the electrical system according to the invention guarantees the intrinsic safety of the ignition circuit at the time of its inspection. Therefore, blasting operations can be carried out under normal operating conditions without the need for additional gas concentration measurements and safety safeguards. The circuit according to the invention also excludes the possibility of performing blasting operations without performing a supply line inspection.

The use of semiconductive material in the construction of the supply line offers the advantage in the resistance of the supply line against charging by electrostatic charges and removes the source of danger.

Furthermore, the circuit according to the invention is a guarantee against a dangerous contact voltage, eliminating the possibility of detonators detonating with a small measuring current.

The solution according to the invention is easy to implement and the cost of its full implementation is minimal with respect to the final effect, which means a similar level of safety to that achieved with expensive power cables of special construction.

The figure shows schematically the wiring of the electrical system to ensure the safety of the supply line during blasting operations, against the danger of ignition of the surrounding explosive atmosphere and increase of the firing reliability, where the high-frequency oscillator 1 with power supply 2 produces a high-frequency signal. rectified by rectifier 4 and wherein the restrictor g provides current and voltage limitation of the voltage injected between the cores 6 or 6 'with insulation 8 or g * and the middle selector 2 of the supply line g with the semiconductive mass 10 with the ignition network 15 connected an evaluation unit 11 which monitors the energy conditions in the ignition circuit and causes a local signaling element 12 to be triggered when a hazardous situation occurs.

A lock circuit 13 can also be connected to the output of the signaling unit 12 to disable the igniter 14 from operating in the event of a hazardous situation.

Claims (2)

SUBJECT OF THE INVENTION 1. Connection of the electrical system to ensure the safety of the supply line during blasting operations against the danger of ignition of the surrounding explosive environment and to increase the reliability of the firing, which system is a power supply, oscillator, transformer and other elements and supply line in two insulated conductors and overlapping the center conductor, characterized in that the power supply (2) is connected to a high-frequency oscillator (1), the output of which is a transformer (3), connected by its output to a rectifier (4), to which the limiter (5) is connected. connected by a center conductor (7), a first conductor (6) or a second conductor (6 ') to the supply line (9) and to the evaluation unit (11) to the output of which the signaling part (12) is connected. Electrical system connection according to claim 1, characterized in that a blocking circuit (13) is connected to the output of the signaling part (12), at the output of which the igniter (14) is connected.