ultrasonic flaw detector
Principle:
Whenever there is a change in medium, then the ultrasonic waves will be reflected. This is the principle used in ultrasonic flaw detector.
Working
(i) The pulse generator generates high frequency waves and is applied to the piezo electric transducer and the same is recorded in the CRO (Pulse A) for reference.
(ii) The piezo electric crystals are resonated to produce ultrasonic waves.
(iii) These ultrasonic waves are transmitted through the specimen.
(iv)These waves travel through the specimen (metal) and is reflected back by the other end. (v) The reflected ultrasonic waves are received by the transducer and is converted into electrical signals. These reflected signals are amplified and is recorded in the CRO(Pulse B). (vi) If the reflected pulse (Pulse B) is same as that of the transmitted pulse (Pulse A) as shown in Fig.1, then it indicates that there is no defect in the specimen.
(vii) On the other hand, if there is any defect on the specimen like a small hole (or) pores, then the ultrasonic waves will be reflected by the holes.
(viii) These defects give rise to another signal (pulse Z) in between pulses 'A' and 'B' as shown in fig 2.From the time delay between the transmitted and received pulses the position of the hole can be found. (ix) From the height of the pulse received the depth of the hole can also be determined.
(ii) The piezo electric crystals are resonated to produce ultrasonic waves.
(iii) These ultrasonic waves are transmitted through the specimen.
(iv)These waves travel through the specimen (metal) and is reflected back by the other end. (v) The reflected ultrasonic waves are received by the transducer and is converted into electrical signals. These reflected signals are amplified and is recorded in the CRO(Pulse B). (vi) If the reflected pulse (Pulse B) is same as that of the transmitted pulse (Pulse A) as shown in Fig.1, then it indicates that there is no defect in the specimen.
(vii) On the other hand, if there is any defect on the specimen like a small hole (or) pores, then the ultrasonic waves will be reflected by the holes.
(viii) These defects give rise to another signal (pulse Z) in between pulses 'A' and 'B' as shown in fig 2.From the time delay between the transmitted and received pulses the position of the hole can be found. (ix) From the height of the pulse received the depth of the hole can also be determined.