| 摘要 |
PURPOSE:To enable a remote monitoring of the height, flow direction and spread range of smoke by measuring time covering from the emission of a sound wave to the arrival of the reflected wave. CONSTITUTION:Transmitters, for example, speakers 31-3n of a sharp directivity,and receivers provided close thereto, for example microphones 41-4n are so arranged in a pair on the ground that transmitting and receiving surfaces of sound waves look upward vertically at intervals of 22.5 deg. corresponding to an angle defined at an equal interval on the circumference with a desired radius centered on the stack, for example, bearings N, NNE, NE, NEE, E.... With such an arrangement, the height and the vertical spread range of smoke can be detected continuously when it is unseen or even at night by emitting sound waves sequentially. In addition, the flow direction and the horizontal spread range of the smoke can be detected continuously based on the bearings of setting the receivers which have received the reflected waves and angle ranges between the receivers which have received the reflected waves. |
