SU894558A1 - Ultrasonic echo-pulse flaw detector - Google Patents

Description

(54) ULTRASONIC ECHO-PULSE DEFECTOSCOPE

The invention relates to non-destructive ultrasonic testing and can be used to control the engineering and other industries. A ultrasonic echo-pulse flaw detector containing a synchronizer, a transducer, an amplifier, a selector, a time interval generator and a counter 1 is known. A disadvantage of the known flaw detector is the low reliability of the control. The closest to the invention in technical essence and the achieved result is an ultrasonic pulse echo pulse detector containing a series-connected synchronizer, probe pulse generator, transducer, amplifier, first selector and reversible counter indicator and pulse generator, the input of which is connected to the output of the first selector 2. The disadvantage of the known flaw detector is the low reliability of the control, since both the signals from the defect and the noise are fixed equally. The purpose of the invention is to increase the reliability of the control. The goal is achieved by the fact that the ultrasonic flaw detector is provided with a second selector, the first input of which is connected to the output of the reversible counter, the second input to the output of the first selector, and a frequency divider connected between the second selector and the indicator, the output of the pulse generator is connected to the second input of the reversible counter, the synchronizer output is connected to the second input of the first selector, the output of which is connected to the third input of the reversible counter. The drawing shows a block diagram of an ultrasonic pulse echo flaw detector. The ultrasonic pulse echo flaw detector contains synchronizer 1 connected by a synchronizer 1, generator 2 probe pulses, converter 3, amplifier 4, first selector 5 and reversible counter 6, indicator 7, generator 8 of pulses whose input is connected to the output of the first selector 5, second selector 9 , the first input of which is connected to the output of the reversing counter 6,

the second input is to the output of the first selector 5, and a frequency divider 10 connected between the selector 9 and the indicator 7.

The output of the generator 8 pulses connected to the second input of the reversible counter 6. The output of the synchronizer 1 is connected to the second input of the first selector 5, the output of which is connected to the third input of the reversing counter 6.

Ultrasonic echo pulse flaw detector works as follows.

The synchronizer 1 pulses with its pulses a generator 2 of probing pulses, which excites the transducer 3. The pulse reflected from the defect is received by the transducer and converted into an electrical signal that enters the amplifier 4. The amplified signal passes through the first selector 5 to the input of the reversible counter 6.

The leading edge of the strobe pulse of the selector 5 starts the operation of the generator 8 pulses and the reversing counter 6, which is filled with pulses from the generator 8. Here two cases are possible: in the absence of a signal from the defect by the falling edge of the strobe pulse of the selector 5, the counting stops and the reversible counter 6 is reset without changing its mode of operation, when the signal at the output of the selector 5 comes from the defect, the count stops and the subtractive mode of the reversible counter 6 is set.

The subsequent cycle of operation in the first case repeats unchanged, and in the second case, the leading edge of the strobe pulse of the selector 5 starts the generator 8 and the reversible counter 6, which starts the subtraction of the pulses. Upon reaching the zero state of the reversible counter 6, the counting is stopped, the totalizing operating mode of the counter is restored and the second selector 9 is started, which passes the signal from the defect, the repetition period of which is equal to the synchronization period. The duration of the strobe pulse of the selector 9 is selected in the range of up to lOt, where t is the period of ultrasonic vibrations. Thus, the selection zone is reduced N times.

N,

2

where g is the duration of the time interval of the selector 5; Tj - the duration of the time interval

selector 9.

Moreover, the area of the selector 9 is set at the place of occurrence of the signal from the defect at 0 of the previous cycle. The signal from the defect passes the selector 9, the frequency divider 10 and is fixed by the indicator 7. Other signals that have passed the selector 5 are delayed by the selector 7.

The described flaw detector makes it possible to reduce the probability of detecting repetitive non-periodically or with a period that is not equal to synchronization, electrical and acoustic noise, and to increase the reliability of the control.

Claims (2)

1. USSR Author's Certificate No. 580504, cl. G 01 N 29/04, 1977. 2. USSR author's certificate No. 605168, cl. G 01 N 29/04, 1976 (prototype).