SU1370551A1 - Sounding pulse generator for ultrasonic multichannel flaw detector - Google Patents

Abstract

The invention relates to non-destructive testing and can be used in the technique of ultrasound testing. The purpose of the invention is to increase the operating stability of the generator by combining the excitation circuits of the transducers in each channel. The transducers 5 - 7 are excited and their information is retrieved alternately through the secondary windings of pulse transformers, the inductive resistance of which is controlled by alternately closing the primary windings. The frequency and sequence of switching channels is set by the generator P and decoder 14, I or S (L

Description

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The invention relates to non-destructive testing and can be used in the technique of ultrasonic inspection of products.

The purpose of the invention is to increase the stability of the generator by combining the excitation circuits of the transducers in each channel.

The drawing shows a block diagram of a probe pulse generator for an ultrasonic multichannel flaw detector.

The probe pulse generator for an ultrasonic multichannel flaw detector (not shown) contains a pulse distributor 1, connected to the outputs of the last control - the inputs of N transistor switches 2–4, the number of which is equal to the number of control channels, N electroacoustic transducers 5–7 and N pulse transformers 8-10, the pulse distributor 1 is made of a serially connected clock generator 11, the output 12 of which is intended to be connected to the external synchronization input of the flaw detector, a binary counter 13, capacitively the value of which is set equal to the number of control channels and decoder 14, the outputs

which serve as outputs of pulse distributor 1, in each channel a transistor switch (2–4) is connected in parallel with the primary winding of a pulse transformer (8–10), the secondary winding of which is connected in series with an electroacoustic converter (5–7), the secondary terminals of the secondary windings m | pulsed transformers 8-10 of each channel are combined (pin 15) and are intended to be connected to the generator-receiving path of the flaw detector.

The device works as follows.

The clock generator 11 generates rectangular pulses that arrive at a certain frequency at the same time at the output 12 for external synchronization of the flaw detector (not shown) and the counter of pulses 13, whose capacity is equal to the number of control channels. The counting of pulses produced by the generator 1I is in the binary code 1-2-4-8, from the output of the counter 13, which serves as a divider, the signals of the binary code are sent to the address inputs binary

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decimator 14, which converts them into a decimal code, and at its outputs alternately, rectangular pulses delayed one relative to another for a time equal to the duration of the impulse itself. The duration of these pulses is equal to the period following the rectangular pulses of the clock generator 1 1 and determines the duration of one channel of the multichannel flaw detector

From each output of the binary to the local decoder 14, the square-wave pulses arrive at the bases of transistor switches 2–4 and open them alternately. For the time of the open state, for example, the transistor switch 2 of the first channel, the primary winding of the pulse transformer 8 closes, because the resistance of the collector-emitter circuit of the open transistor switch 2 is insignificant (about 0.1-10 Ohms). As a result, the inductive resistance of the secondary winding of this pulse transformer 8 becomes almost zero, as a result of which the output of the generator of probe pulses of the flaw detector is connected via pin 15 directly to the electroacoustic reobrazovatelyu 5, connected in series with this winding.

Under the action of external clock pulses of the clock generator 11, arriving at pin 12, the probe pulse generator is started. The voltage of the probe pulses is applied to the piezoelectric transducer 5 and excites it. Ultrasonic vibrations are introduced through a layer of acoustic fluid by a piezoelectric transducer 5 into a controlled article (not shown). Reflected, for example, from opposite surfaces of the product or from a defect, the echosignals that are in the zone of action of the first channel are received by the piezoelectric transducer 5, converted by it into electrical pulses and then through the secondary winding of the same pulse transformer 8 are fed through pin 15 to the receiving flaw detector amplifier path. On the indicator block of the latter, the control result is obtained.

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products on the first channel. At this time, there is no control over all other channels, since piezoelectric transducers 6–7 are practically disconnected from the generator output of probe detectors of the flaw detector due to the large inductive resistances of the secondary windings of pulse transformers 9–10 at the working frequency of probing pulses. Similar to the first channel described above, the other channels of the device work

By combining the excitation circuits of the transducers in each channel, the parameters of the excited pulses are identical, and the stability of the generator,

Claims (1)

Invention Formula Probe pulse generator for an ultrasonic multichannel flaw detector containing a pulse distributor connected to the outputs of the latter by control inputs 14 N transistor switches, the number of which is equal to the number of control channels, N electroacoustic transducers and N pulse transformers, which is so as to increase the generator operation stability by combining the drive circuits of the transducers in each channel, the pulse distributor is made of series-connected clock generator whose output is intended for connection to the external synchronization input of a flaw detector, a binary counter and a decoder, the outputs of which serve as outputs tel pulses in each settee transistor switch connected in parallel with the primary obmot Coy pulse transformer, the secondary winding is connected in series with the electro-acoustic transducer, the free terminals of the secondary windings of pulse transformers each channel are combined and are intended for connection to the generator-receiver path flaw.