Patent GB-241505-A (GB)
Title: Improvements in method and apparatus for the direct measurement or the recording of depths or distances at sea by means of the ultra-audible echo
IPC: G01S1/72
Filed: 1924-12-31
Abstract: 241,505. Langevin, P. Oct. 16, 1924, [Convention date]. Addition to 227,801 and 230,013. Determining distances acoustically; recording signals.-The inventions described in the parent Specifications are modified in that one of the valves of the circuit-changing device described with reference to Fig. 3 of Specification 230,013 is omitted and the arrangement is made more sensitive and adapted for control from a distant station means are provided to avoid excessive tension on the grid of the first amplifying valve on the emission of a signal, and the recording device of Specification 227,801 is modified. Determining distances acoustically. Fig. 1 illustrates the modified arrangement for automatically starting the current through the valve L2 when a signal is emitted, and for interrupting the circuit when the echo is received. In the circuit of the valve L2 are arranged a resistance R1 having a considerable value, a ballistic galvanometer G, B and shunt resistances S1, S3, while in the circuit of the valve L3 are arranged an ammeter M, a resistance R2 of the same value as R, and shunt resistances S2, the resistances S1, S2 being simultaneously varied so as to adjust the current in the galvanometer to the value for which the apparatus has been standardized. The valves L2, L3 are interconnected in the manner described in Specification 230,013 and the emission circuit L, Q is coupled inductively through a shunted condenser C, R with the grid of the valve L3, so that, on the emission of a signal, the current is started in the plate circuit of the valve L2 and is not affected bv the osrilliations acting upon the amplifying valve L1 but is interrupted only on the receipt of the echo. The potential of the grid of the valve L1 is adjusted to the value for which the circuit-changing device is most sensitive by a potentiometer P. Shunts are provided in connection with the batteries e to maintain constant the voltage applied by them to the plates of the valves. The arrangement for reducing the tension on the grid of the first valve L1 consists in including a resistance R10 in the grid circuit, Fig. 2. During reception, when the variations in potential are small, the resistance of the valve is high in comparison with that of R10 and the latter has little effect, but when a signal is emitted and the variations in potential are large, the resistance R10 is of the same orrder as that of the valve and the fall of potential across the resistance is considerable. Distant control of the sounding apparatus. The galvanometer GB. ammeter M, control switches K1, K2, Fig. 3, and an indicator valve L10 may be mounted on a control board located, with the recording device, in the navigation quarters of a vessel, and the sounding apparatus disposed in the hold. In addition to the valves L1, L2 and L3 the arrangement comprises an oscillating circuit L20, C20 including a Ruhmkorff coil R and spark gap E coupled inductivelv with the emission circuit L, Q, a receiving coil B, coupled with the circuit L, Q and associated with highfrequency amplifiers HF, with a detector valve D, and with low-frequency amplifiers BF, a coil B2 associated with the circuit-changing device, and a relay R, which is energized on closing the switch K1 so as to complete the filament circuits and also to close a circuit through a second relay R2 and the indicator valve L10, the latter showing that the apparatus is ready for making measurements. The current through the relay R2 is insufficient to operate its armature and so effect an emission of signals until the valve L10 has been short-circuited by closing the switch E2. Recording signals. The recording device comprises a wheel. with a number of emission contacts a, Fig. 4, mounted on the shaft of a second wheel f having a corresponding number of contacts S1 - - arranged above the paper recording hand b, which may be moved either uniformly or be associated with the log device employed on the vessel. Below the wheel f the paper band is passed through a curved guide g. The locus of the points produced by the emission of signals forms a base line, and the locus of the points produced by the reception of signals after varying time intervals is a curve giving the contour of the sea bottom at a distance from the base line corresponding to the actual depth.