Patent ID: 6631097
Filing Date: 2003-10-07
Classification: G01C,G01F,G01S,Y10S

Abstract:
A sonic water level measuring method for fixing an original measuring point on the upper of a wave-guide tube in the form of a pipe measuring times that it takes for a sonic pulse to be transited through air medium in a wave-guide tube toward a water surface and transited back to an original measuring point after being reflected on the water surface and computing a distance from the original measuring point to the water surface comprising steps of:arranging two microphones constituted as a sound receiver to be spaced away in an interval l1 from each other below a sonic pulse generator on the upper of the wave-guide tube; securing an interval l2 between the water surface and the reflecting surface of a sound-reflecting cylinder with a float integrated with a sound reflecting cylinder being submerged in the water; measuring times t1, t2 and tL that it takes for the sonic pulse to transit the intervals l1 and l2 and to go up and down a distance L from a first microphone to the water surface, respectively; calculating the distance L from the first microphone to the water surface as follows: L=tL2&CenterDot;12&it;(l1t1+2&it;l2t2)=14&it;tL&CenterDot;(l1t1+2&it;l2t2)Only, l2 is selected as follows: l2&GreaterEqual;NC22&it;fwherein, f is a sonic pulse frequency, N is the number of period until the sonic pulse is completely damped and C2 is a maximum sound velocity that can be expected in the interval l2.