GB279803A - Improvements in apparatus for sounding, or signalling comprising a gaseous discharge lamp - Google Patents

Abstract

279,803. Soc. de Condensation et d'Applications MÚcaniques, and Touly, M. Oct. 28, 1926, [Convention date]. Determining distances acoustically.-In apparatus for the acoustic determination of depths and for signalling low-voltage electric discharge lamps containing low-pressure gas and having two or more electrodes are lighted or extinguished by the application of an over or under voltage at the moments of emission and reception of the compression wave. The luminous discharge starts and stops at well-defined potentials, the stopping potential being lower than the starting potential. An electric discharge lamp 6 which may be a neon lamp having its electrodes covered with alkaline earth, is arranged in circuit with a source 7, a potentiometer 8, a transformer 5 and the armature 10 of a relay 9, the winding 11 of which is connected to a switch 3 through a condenser 12. Highfrequency current from a transmitter 1 supplied by a source 2<1> is converted by a piezo-electric condenser 2 into ultra-audible waves, the reflected impulses being also received and re-converted by the device 2, which is connected through an amplifier 4 to the transformer 5. At the moment of emission the switch 3 is closed, the condenser 12 discharging through the relay 9, which opens the lamp circuit and extinguishes the lamp 6. The discharge time of the condenser 12 is greater than the time of emission. When the echo returns, the energy from the amplifier 4 and transformer 5 applies an over-voltage to the lamp 6 sufficient to light it, the lamp remaining alight until the emission of the next signal. The dark interval may be measured by mounting a mirror 55 and a lens 56 on an arm secured to a rotating shaft 54, an image 57 of the lamp 6 being thus displaced around a circular graduated scale 58. By using the resistance 7<1> and the connection shown in broken lines, and by regulating the voltage of the battery 7 by means of the potentiometer 8, the emission and reception of the signal may be used to apply an under. voltage and extinguish the lamp. The switch 3 and the relay 9 may be actuated mechanically by the same device, for example by two cams on the shaft of the motor driving the shaft 54. In a modification the lamp is arranged to give flash signals, coupling between the amplifier 4 and the circuit of the relay lamp being established by autotransformers, condensers, resistances, &c. A lamp with an auxiliary external electrode or magnetic field may be used for starting. In a further modification a relay in the lamp circuit controls an electric timing device in another circuit.