摘要:
The present invention relates to a protective circuit (30) for intrinsically safe electromagnetic actuators operating at the voltage of a power supply approved for underground mining, for switching electrohydraulic valves in underground mining, comprising a coil (11) connected to a first potential (2) and a second potential (3) of the power supply and associated with at least two spaced-apart short-circuit means (12) connected in parallel with the electromagnetic actuator coil (11) for short-circuiting the coil in the event of a reversal of the potential of the coil voltage. In accordance with the present invention the protective circuit comprises a semiconductor switch (T3) which is inserted between the coil (11) and the second potential (3) and, in the event of a voltage reduction or potential reversal, isolates the coil (11) from the second potential, so that the discharge from the coil (11) has no adverse effect on the energy supply system or the intrinsic safety.
摘要:
A protective circuit (30) for intrinsically safe electromagnetic actuators operating at the voltage of a power supply approved for underground mining, for switching electrohydraulic valves in underground mining, comprising a coil (11) connected to a first potential (2) and a second potential (3) of the power supply and associated with at least two spaced apart short-circuit means (12) connected in parallel with the electromagnetic actuator coil (11) for short-circuiting ting the coil in the event of a reversal of the potential of the coil voltage. In accordance with the present invention the protective circuit comprises a semiconductor switch (T3) which is inserted between the coil (11) and the second potential (3) and, in the event of a voltage reduction or potential reversal, isolates the coil (11) from the second potential, so that the discharge from the coil (11) has no adverse effect on the energy supply system or the intrinsic safety.
摘要:
The invention employs pressure and displacement sensors for the automatic monitoring and adjustment of the pre-tension of endless belts, in the form of chains or the like, which sensors determine the pressure in the cylinder space and the movement of the piston of the tensioning cylinder, and the measuring signals from which sensors are evaluated by an electronic evaluation and actuation unit. In this respect the evaluation and actuation unit calculates from the measuring signals the changes in pressure which occur over a predetermined partial stroke of the piston of the tensioning cylinder, wherein these changes in pressure reflect the state of tension of the chain belt. When the chain tension is incorrect, the evaluation and actuation unit can therefore control the tensioning cylinder so that the optimum chain tension is set automatically.
摘要:
An intrinsically-safe battery power supply for electrical equipment in underground mining and in other areas exposed to the danger of explosion is disclosed. The power supply includes at least one chargeable storage battery cell disposed in a battery housing. At least one storage battery cell comprises a chargeable lithium storage battery cell and the battery housing is configured to be pressure-resistant and to receive all lithium storage battery cells in a manner so as to be protected from explosion. The pressure-resistant configuration of the battery housing enables the use of lithium storage battery cells in underground mining. Once the battery power supply fulfills all requirements of ignition protection certification, even modern types of lithium storage battery cell can be disposed in the battery housing.
摘要:
A housing cover for a solenoid housing operable for accommodating solenoids for switching hydraulic directional valves is disclosed. A housing cover box has a plurality of side walls, a top side, and an open bottom side, with first and second actuating guides for guiding first and second solenoid control push rods being located on the top side. A plug connector is located between the actuating guides. At least one screw clearance hole is located at each corner of the housing cover box for locating a screw for joining the housing cover box to the solenoid housing. A sealing plate is located between the housing cover box and the solenoid housing, and at least one mounting foot is located at a corner and on a bottom surface of the housing cover box. A tubular spigot is aligned with and extends each screw clearance hole.
摘要:
The present invention is an individual controller for shield support frames in underground mining, having a shallow box-shaped housing for holding microelectronics comprising a top wall, a bottom wall, two side walls, a front wall and a back wall, with receptacles for connecting cable plugs from sensors and actuators and with at least one socket for connecting a plug of a cable for communicating with an adjacent individual controller.
摘要:
A method for controlling the main and auxiliary drives of conveyors, for example, in underground mining. The drives are controlled as a function of the loading of the conveyor in such a way that in a low load range of the conveyor the auxiliary drive produces a higher output (20.sub.I) than the main drives and as the load increases the output advantage of the auxiliary drive in relation to the main drives is reduced. This special load distribution to auxiliary and main drives has the advantage that sagging of the conveyor element, for example the chain of a scraper chain conveyor in the inaccessible and concealed lower strand, close to the main drive, can be prevented. The risk of damage to the machine frame or conveyor chain is thereby reduced.
摘要:
The present invention relates to a method for operation of an electro-magnet (2, 3) connected to an intrinsically safe direct current circuit which can be switched under control between two positions for the operation of the closing body of a hydraulic valve (5, 6), whereby using of an electronic control unit, the coil windings of the electro-magnet (2, 3) are taken in the pull-in phase of the armature of the electro-magnet to an exciting current and in the retaining phase of the armature to a lower retaining current as opposed to the excitating current, and a device with which the retaining current reduction is realized.
摘要:
Longwall face equipment for use in extraction in underground mining, comprising electrohydraulically operated support units each having a support controller 6, with at least one power unit being provided that supplies at least two support controllers 6 of differing support units with power, and with a bi-directional coupler being connected between the power unit and the at least two support controllers 6 and providing galvanic isolation between the power unit and the support controllers 6 and/or groups I, II of support controllers 6. The couplers permit communication between the two support controllers 6 and/or groups I, II of support controllers. In order to simplify the arrangement of the face, the coupler 12 is integrated into the power unit 11 or is flanged directly onto the housing of the power unit.
摘要:
The warning tone transmitter (10) according to the invention has a piezoelectric horn element (12) with two input connectors (29, 30) for the application of the supply voltage at a determined frequency and has a circuit arrangement (14) fed from the current supply, which generates the supply voltage. In order to be able to receive confirmation that the horn signal is actually generated by the warning tone transmitter (10) and in order to be able more easily to calibrate the warning tone transmitter (10) such that it is driven at its resonant frequency the piezoelectric horn element (12) has an additional output connector (34), which, when the horn element (12) is fed with the supply voltage, generates an answering signal taken to the circuit arrangement (14) if the piezoelement is actually oscillating. The magnitude of the answering signal is a value for the sound volume of the warning tone transmitter (10).