GB2172450A - Spark-proof power supply system for remotely operated devices - Google Patents

Abstract

A power supply unit 1 is connected to controlled stations 3 via a line 2 and junctions 7 leading to branch lines 8. Each station 3 has a unit 9 at a junction 7 and a unit 10 at the remote end of the corresponding branch 8. The unit 10 includes a main voltage stabilizer 14 and a load 15, and the unit 9 includes an additional voltage stabilizer 11 having outputs supplying both a switch 13 at the input to branch 8 and an address decoder 12 which controls the switch 13. The units 3 are activated in succession. If a sensor 4 detects a break or short circuit in the branch 8 of an activated unit 3, a protection circuit 5 disconnects the power source 6 in the supply 1. <IMAGE>

Description

SPECIFICATION Spark-proof power supply system for remotely operated devices This invention relates to automatics and remotely operated devices and, in particular, to centralized power supply systems for remotely monitored and controlled objects located at plants with a dangerously explosive atmosphere and specifically to spark-proof power supply systems for remotely operated devices.

The invention can be is especially applicable to power supply of spark-proof voltage to remotely controlled stations telemechanical systems, remotely monitored and controlled objects located at plants with a dangerously explosive atmosphere in order to reduce the power consumption and improve the reliability of the system and the spark-proof power of the power supply.

Centralized supply of spark-proof voltage to remotely controlled stations of telemechanical systems and remotely monitored and controlled objects, such as pickups, sensors, actuators, etc., located at plants and works with a dangerously explosive atmosphere, such as coal mines, is a difficult enough task involving safe operation of various devices in the event of a discharge caused by a rupture of shorting of communication lines. In this case the discharge uses the power accumulated in distributed inductances and capacitance in addition to that of the voltage source, which can be the cause of an explosion.

Known power sources are usually provided with spark proofing units which isolate the discharge circuit from the power source in the event of a shorting or rupture of the communication cable. But this is evidently insufficient to prevent an explosion, since the power accumulated in the distributed inductances and capacitors of the cable line can still cause an explosion of the atmosphere in case the communication line is ruptured or short circuited, even if the power source is disconnected by the spark proofing device.

The safety of multiplex communication lines used for the power supply of remotely controlled stations of telemechanical systems and remotely monitored and controlled objects has been somewhat improved by separating the cable line by shunts, diode bridges, for example. The spark-proof power of the source can be increased because the power applied to the point of rupture or shorting of the circuit was accumulated by the distributed inductance and capacitance of only a part of the communication line.

The power accumulated in the distributed inductance and capacitance of branches is isolated because it is shunted.

The invention provides a spark-proof power supply system for remotely controlled devices, comprising: a power supply unit composed of a discharge start pickup connected in series to a spark protection element, and to a power source whose output is connected to an input of the discharge start pickup; a communication line connecting, via junction points and branch lines, the power supply unit to individual remotely controlled stations, each such station being equipped with a main voltage stabilizer whose input is connected to a branch line, while an output thereof is connected to inputs of a controlled station address decoder and a functional unit, according to the invention, said controlled station address decoder is placed in a branch junction point and provided with an additional voltage stabilizer whose input is directly coupled to the communication line, while an output thereof is coupled to the input of the controlled station address decoder, and with a controlled switch whose input is coupled directly to the communication line, while an output thereof is coupled to a branch line, a controlled input of said switch being connected to the output of the address decoder.

This arrangement permits separation of a damaged portion of the line, where a rupture or short circuit occurred, from the rest of the system, thus maintaining it partially operable. This results in a substantial improvement of efficiency of remotely controlled systems since their effective range is expanded and they become much more reliable in operation.

The invention will now be described in more detail, by way of examples, with reference to an accompanying drawing which shows a skeleton diagram of a spark-proof power supply system.

A spark-proof power supply system for remotely operated device comprises: a power supply unit 1 connected, via a branched communication line 2, to controlled stations 3', 3" ...3n. The power supply unit 1 comprises several series-connected elements, such as a discharge start pickup 4, a spark protection element 5, and a power source 6 whose output is connected to an input of the discharge start pickup 4.

The communication line 2 comprises junction points 7 and branches 8 whose number can be one, two or more (I, II).

Each controlled station 3 comprises: a unit 9 installed directly in the junction point 7 of the communication line 2, and a unit 10 located at remotely controlled and monitored objects. The unit 9 installed directly in the junction point 2 comprises: an additional voltage stabilizer 11 built, for example, around cutoff mode field-effect transistors, the input thereof being directly connected to the junction point 7, while the output is connected to an input of an address decoder 12 of the controlled station 3; a controlled switch 13 built, for example, around a switch-mode transistor or a hermetically sealed relay, whose input is connected directly to the voltage stabilizer 11 and whose output is connected to the beginning of the branch 8, while a controlled input of said switch 13 is connected to an output of the address decoder 12 of the controlled station 3.

Each unit 10 of the controlled stations 3 comprises the following series-connected elements: a main voltage stabilizer 14 built, for example, around stabilizer diodes equipped with a powerful transistor as an output element, and a functional unit 15 composed of modules for telemetry, remote indication, remote control and others (not shown).

The circuit of a spark-proof power supply system, operates as follows.

As voltage is supplied from the power supply unit 1 to the communication line 2, all address decoders 12 are energized through the additional voltage stabilizers 11. Supply voltage from the power source 6 of the power supply unit 1 is not fed to the branches 8 of the communication line 2 since the controlled switches 13 of the controlled stations 3 are closed. When a command is delivered to the next-in-turn controlled station, for example, the controlled station 3', the address decoder 12 of the unit 9 sets the controlled switch 13 open and the latter feeds voltage from the power supply unit 1 via the communication line 2 to the branch 8 of the controlled station 31. The voltage fed to the unit 5 of this controlled station 3' starts the operation of the functional unit 15 via the main voltage stabilizer 14.

The unit 10 of said controlled station starts operating in accordance with the control commands fed from the control unit (not shown).

When a command is delivered to the next-in-turn controlled station, the supply voltage at the controlled station 3' is cut off by the address decoder 12 via the switch 13 and this controlled station 3 is switched to a holding condition, the branch 8 together with the unit 10 of the controlled station 3 is deenergized.

All controlled stations 3,3', 31 ...3n operate in a similar manner. In emergency conditions, in case, for example, of a break or short circuit in the branch 8 of the controlled station 3' or in the unit 10 of this controlled station, when a command arrives to the controlled station 3', the switch 13 opens and the spark protection element 5 and the discharge start pickup 4 of the power supply unit 1 operate and disconnect the power source 6. The system is brought to the initial state.Further on, as voltage is fed frdm the power supply unit 1 to the communication line 2 and a selection command is supplied to the next-in-turn controlled station, for example, the controlled station 311, the system operates normally, since the supply voltage is not fed to the damaged branch 8 of the controlled station 31 and the power supply unit 1 is not disconnected.

The use of a spark-proof power supply system for remotely operated devices located at plants with a danerously explosive atmosphere contributes to a substantial reduction of power consumption from a centralized power source, permits sequential redistribution of the source power among users. This can help increase the maximum distance along the communication line from the control point to controlled stations without resorting to additional amplification of signals. In addition, considering that the address portion of the controlled station is brought out to the unbranched part of the communication line, and that the branches and basic components of the controlled stations are completely disconnected, the electrical capacitance and inductance of the communication line in the holding condition are substantially diminished. This permits the use of a higher spark-proof power of the supply source, the system becomes much more reliable since it is possible to detect the faulty branch from the control center and disconnect it in order to let the rest of the system function normally.

Claims (2)

1. A spark-proof power supply system for remotely operated devices, comprising: a power supply unit composed of several series-connected elements, such as a discharge start pickup, a spark protection element, and a power source whose output is connected to an input of said discharge start pickup; a tree-like communication line comprising junction points and outgoing branches connecting said power supply unit with individual controlled stations; each said individual controlled station comprises: a main voltage stabilizer installed at the terminal point of said branch line, whose input is connected to said branch line, an additional voltage stabilizer installed directly in said junction point and connected to said tree-like communication line; an address decoder of said controlled station, which is also installed in said junction point of the branch, whose input is connected to an output of said additional voltage stabilizer, and having a functional unit located at said terminal point of said branch line, whose input is connected to an output of said main voltage stabilizer; an controlled switch having two inputs and one output, one input of said switch being connected to the output of said additional voltage stabilizer, another controlled input thereof being connected to the output of said address decoder, while the output is connected directly to the initial portion ofthe branch line.

2. A spark-proof power supply system substan tiaily as described herein with reference to the accompanying drawing.