ULTRASONIC TEMPERATURE SENSOR AND ULTRASONIC WAVEGUIDE CONNECTOR FOR APPLICATION THEREOF

摘要

PURPOSE: To obtain the temperature sensor which is suitable for aircraft fire detection by providing a temperature response means which varies the acoustic impedance of an ultrasonic wave waveguide at points determined in a longitudinal direction of the ultrasonic wave waveguide and partially reflecting arriving ultrasonic wave pulses. CONSTITUTION: The sensor 10 is constituted by providing the lengthwise ultrasonic wave waveguide 12 in a cylindrical lever or rod 14, dividing the waveguide 12 into plural areas by cut parts 22, and filling the cut parts 22 with low-melting-point alloy 24 having acoustic impedance nearly equal to that of the lever 14. Further, an ultrasonic wave pulse transmitter receiver 18 is coupled with one end part 16 of the waveguide 12 and sends longitudinal ultrasonic wave pulses, and the transmitter receiver 18 is further coupled with a timing circuit 20 which measures the time difference between a sent pulse and a reflected pulse. If the alloy 24 in one cut 22a is fused owing to a fire, the acoustic impedance of the waveguide 12 is remarkably varied at the cut part 22a and the reflected pulse is made to arrive earlier than its expected arrival time, which is detected by the transmitter receiver 18. Consequently, the position of the fire can be indicated with the time difference measured by the timing circuit 20.