| 摘要 |
PURPOSE:To make the sure calculation of wall thickness distributions possible in the measurement of the thickness of a pipe by determining the rate of eccentricity of an inside diameter from the transmission intensity of radiations and the outside diameter in the transmission direction. CONSTITUTION:A radiation of intensity I0 assuming an angle theta to a Y-axis by passing through a central point O on the outside circumference of a pipe is considered, and distance OA=R1, OA'=R2 are assumed. The inside circumference of the pipe is a circle of a radius (r), and the center thereof is apart by deltar from the X-axis, and deviates by thetaA from the Y-axis. If the transmission intensity I is measured, a coefft. of transmission K is determined from the coeff. of attenuation in metal and the IO. From this and the outside diameter D in the direction theta, K'=(D-K)<2>/4 is operated. On the other hand, as is evident from the theoretical equation K'=r<2>-deltar<2>.sin<2>(theta-thetaA), eccentricity exists if the measured value K' exhibits periodical fluctuations. The square root of the difference between the max. and min. values of the K' is the magnitude deltar of the eccentricity and the direction where it maximizes is thetaA. Thereby, the wall thickness distributions are calculated. |
