Remote thermometer for inaccessible and hazardous equipment - has temp. sensitive oscillator driving ultrasonic transmitter for high resolution

摘要

The ultrasonic remote thermometer for inaccessible equipment is esp. suitable for temperature measurements on high-voltage transformers or apparatus immersed in corrosive fluids. The temp. sensor uses a miniaturised, quartz-controlled oscillator whose frequency aries widely with small changes in temp. The oscillator output drives a wide-band ultrasonic transmitter. DC supply for the oscillator circuit is derived from an auxiliary winding on the transformer. An ultrasonic transducer fitted to the wall of the tank has a wide-band characteristic and its electrical output drives a frequency meter in an instrument panel. The meter may be calibrated for direct temp. readings. The system is capable of a temp. resolution of 1/100 deg.C.