| 摘要 |
PROBLEM TO BE SOLVED: To control the drive of a blower so that an exhaust gas staying in a tunnel can be unloaded toward the outside of the tunnel effectively and efficiently by accurately measuring wind velocity in the tunnel. SOLUTION: A pair of ultrasonic transceivers 91 and 92 with functions for transmitting and receiving ultrasonic waves is arranged so that the pair has a specific interval in the longer direction of a ceiling 8 in a tunnel in parallel with a center axis in the longer direction of a tunnel 1 and the pair forms an angleθfor receiving an ultrasonic signal being reflected on a road surface 4 each other. Also, a system is composed by a converter 7 for finding wind velocity in the tunnel according to the time difference between the propagation time of ultrasonic waves being transmitted from one ultrasonic transmitter/ receiver to the other of the pair and the propagation time of ultrasonic waves being transmitted from the latter to the former. |
