Remote registering and/or control systems for use with gas-filled or so-called pressurised power and telecommunication cables

摘要

729,813. Indicating leakages in pipes. SINCLAIR, S. Jan. 24, 1952 [Jan. 27, 1950], No. 26257/50. Class 99 (2). [Also in Groups XIX, XXI and XXXVIII] Apparatus for indicating the presence of a fault in a gas-filled electrical cable comprises a plurality of pressure gauges arranged at spaced points along the cable and adapted to close electrical contacts when the pressure at their locality falls below a predetermined value, the closure of the contacts corresponding to any one gauge causing a sequence of electrical pulses characteristic of that gauge to be sent to a central station and thereby operate a selected one of a plurality of signal elements to indicate the location of the fault. The pressure gauges 2 arranged along the gas-filled cable.form parts of units A, B, C, D, E, &c. each comprising contacts a, b and c which are arranged to be bridged by members 1 attached to the pointers 3. In the normal positions of the pointers, the members 1 bridge the contacts a and b so that successive ones of the units A ... E are arranged in series with the conductor 11 from a central station 10. When a fault occurs along the cable, for example at unit A, the pressure there falls and the member 1 bridges the contacts band c, thereby dissociating all succeeding units from the conductor 11 and central station 10 which are then connected instead to impulse-generating apparatus via the contact c. Similar impulse-generating apparatus is associated with each of the units A ... E. Current flowing through the coil 15 attracts the armature 18 which consequently separates the contacts 16 and 17, so opencircuiting the circuit of the coil 15 and releasing the armature 18, whereupon contacts 16 and 17 close and current flows once more through coil 15. The repeated movement of armature 18 thus steps ratchet 20 round and, together with the ratchet 20, a cam 21 carrying a number of lobes corresponding to the particular impulsegenerating apparatus with which it is associated. Thus in the arrangement shown, rotation of the cam 21 causes a single impulse to be sent to the central station where it actuates a rotary switch 9 to position the wiper arm upon the first contact 23 thereof. Each contact is associated with its own indicating circuit comprising a self-holding .relay 27 and visual and audible alarm 25 and 26. A switch 28 is provided for releasing the self-holding relay 27. Each of the units A....E may be provided with further contacts d which may be used to control further apparatus, such as a valve 4 for injecting make-up gas from a cylinder 5 or for releasing fire-extinguishing or fire suppressing fluid.