Distributed temperature sensor

摘要

A distributed temperature sensor comprises an elongate ultrasonic waveguide having a number of zones along its length, each zone having a grating formed on it. This is typically achieved by incorporating uniformly spaced notches or bands (or collars) throughout the zone. The grating spacing in each zone is different, so that each grating reflects a characteristic frequency. This frequency varies as the temperature of the zone varies, so if wide-band ultrasonic pulses are launched into the waveguide, the temperature of each zone can be determined from the reflected frequencies.