Patent GB-696363-A (GB)
Title: Improvements relating to pulse transmitting telemetering systems
IPC: G08C13/02
Filed: 1949-04-06
Abstract: 696,363. Electric indicating systems. FERRANTI, Ltd., and JACKSON, H. June 28, 1950 [April 6, 1949], No. 9325/49. Class 40 (i) [Also in Groups XXIV, XXXVI and XXXVII] A pulse interval equalizer for a telemetering system wherein plural measuring instruments generate electric pulse trains of recurrence frequencies representative of the plural measured quantities which are then combined into a single train of discrete pulses representing the total measured quantity for application to a common meter, comprises a mechanical storage device adapted to receive and store each pulse of the combined input train, a release drive operating at a rate proportional to the mean value of the plural metering 'responses when the storage device contains one or more input pulses but not otherwise and an output interrupter operable in response to the release drive to develop a train of regularly spaced output pulses whose recurrence frequency is proportional to the release rate and which operates the common meter. In a summation metering system for plural sources of electric power, three generators Fig. 4 (not shown) feed a common busbar through their associated power meters, transmitting impulse trains whose recurrence frequencies correspond to the current and thus to the energy outputs of the individual generators to a summator which supplies a combined train of irregularly spaced impulses corresponding to the total energy to a pulse interval equalizer (Fig. 1) wherein they alternately energize windings 11, 12 (Figs. 2, 3) to oscillate a pivoted armature 13 linked to pivoted discs 16, 17 carrying pawls 18, 19 which step a common ratchet 20 once per incoming pulse under control of an escapement 22 operated by a pin 24 on disc 17 and engaging a second ratchet 26. Spindle 10 carrying the ratchets is geared to rotate an internally threaded bush 33 engaging a threaded coaxial spindle 34 constituting the storage member which carries a pinion 35 engaging a pinion 40 driven through gearing by the spindle 41 of a motor having a rotary disc 42, brake magnets 43, voltage windings 44<SP>1</SP>, and current windings 44 energized by a summation current transformer (Fig. 4 not shown) combining the outputs of cur rent transformers in the respective generator outputs so that the motor speed is proportional to the mean of the several metering responses. The arrival of successive input pulses rotates bush 33 relatively to the spindle 34 and screws the latter axially upwards from the initial position proportionately to the number of received pulses. Spindle 41 is then able to rotate pinion 35 in the opposite direction, thus screwing the pinion and its threaded spindle 34 downwards until in the absence of further input pulses the initial position has been reached at which no further downward movement is possible and the motor rotation is arrested. As further input pulses arrive the motor continues to run and produces a continuous downward motion of the spindle 34 and pinion 35 which is balanced against the continuous upward movement due to the incoming pulses, while the motor spindle 41 rotates a cam 56 to operate a changeover contactor Fig. 5 (not shown) to produce an output train of regularly spaced pulses, the number of which in a predetermined integrating period is proportional to the number of input pulses in the same period, which is transmitted to a meter Fig. 4 (not shown) indicating the total load. A limit switch may be provided to accelerate the motor, e.g. by introducing a shunt on the brake magnets when the pinion 35 is raised to a predetermined distance from its initial position. A friction drive may be inserted between the motor and the spindle 41 to allow continuous rotation when the spindle 34 reaches its initial position. Spindle 41 may be driven by a magnet and ratchet device responsive to a pulse train derived from the changeover contactor of a wattmeter energized directly or through a summation transformer from the generator output current transformers. In a modification Figs. 7, 8 (not shown) the storage function is performed by a clock spring which is wound up by a stepping magnet and ratchet energized by the input pulses, and simultaneously allowed to unwind by a magnetically operated escapement pulsed by a wattmeter energized by the output current summation transformer, to rotate a spindle actuating a changeover contactor producing a regularly spaced output pulse train as before. The spring may be replaced by a clock weight and the apparatus is applicable to the metering of other than electrical quantities, e.g. gas or water.