一种用于多界面大声程目标体的超声检测电路

Ultrasonic Inspection Circuit Applied for Multi-interface and Long Path Length Object

多界面大声程目标体检测是超声检测中的难题,由于声程长、反射界面多,导致有效检测声能的大幅衰减,以致常规超声收发系统无法胜任该项工作.针对这一问题,本文设计了一种用于多界面大声程目标体的超声检测电路,该系统发射电路利用555定时器产生长延时的控制脉冲,对电容进行充放电控制,得到超声换能器的高能长延时激励脉冲,回波接收电路主要由电压跟随器,两级放大电路和带通滤波电路组成,以便有效接收回波信号.通过1 500mm钢管液位测量实验得到系统测量的平均相对误差为0.47%,表明该设计对于多界面大声程超声测量具有较高的精度.

It is difficult to inspect multi-interface and long path length object using ultrasonic wave,because the effective sound energy is considerably attenuated by beam spread,material absorption and multi-interface reflection. A novel ultrasonic inspection circuit has been developed to solve the problem with the properties of higher excitation energy and lower repetition frequency. The ultrasonic pulse emission circuit generates high energy and long periodic excitation pulse for ultrasonic transducer by using charging-discharging capacitor,which is controlled by a 555 timer. Echo receiving circuits including a voltage follower; A twostage amplifier and a band-pass filter have also been designed. Experiments have been performed on a steel pipe with 1 500 mm water level and multi-interface. The mean relative error of this designed testing system is 0. 47%. Experimental results show that this circuit system has high precision for long path length and multi-interface object ultrasonic measurement.