GB1182152A - Improved Telemetry System for Pistons and Like Reciprocating Members. - Google Patents

Abstract

1,182,152. Measuring temperature electrically. M. SLAFFER. May 9, 1968 [April 12, 1967], No. 16678/67. Heading G1N. A signal indicative of a parameter, e.g. temperature or displacement, of the piston of a cylinder or a like reciprocating member is transmitted to a first position on an electric conductor to which a receiver is capacitively coupled at another position. As shown, a thermistor 5 on a piston varies the frequency of a transmitter 6 which is connected via capacitor 7 or flexible insulated copper wire to one end of a copper strip attached to the piston connecting rod and then via a capacitance 10 formed between the strip and a stationary curved plate to a receiver 9. The arrangement is such that the value of capacitance 10 remains substantially constant despite movement of the piston. The receiver may be tuned to the input signal frequency or may convert the frequency varying signed to an analogue signal which is recorded. Displacement is measured by causing to vary the proximity of a metal member to an air-cored coil carried by the piston and forming part of a tuned circuit of transmitter 6. For multi-channel operation the strip 8 is arranged to be common to all transmitters and receivers which operate at a plurality of different frequencies. Alternatively, each of a plurality of sensors may be connected to one channel by a switch operating a number of times for each stroke of the piston.