SU911155A1 - Ultrasonic thickness meter - Google Patents

Description

(B) ULTRASOUND THICKNESS MEASURES

The invention relates to non-destructive ultrasonic testing and can be used to control the dimensions of products. A known ultrasonic thickness gauge contains three measuring channels, each of which consists of successively connected generator of probe pulses, a receiving-transmitting transducer, a reflector and a control unit 1. A disadvantage of the known thickness gauge is low measurement accuracy, since the results are influenced by the parameters air environment. The closest to the invention in its technical essence and the achieved result is an ultrasonic thickness gauge containing a reference channel consisting of a series-connected generator of sounding pulses, an emitting and receiving transducer, two measuring channels, each of which consists of an emitting and receiving transducer, probe pulses, the output of which is connected to the radiating transducers of the measuring channels, three counters, a control unit and a reflector 2. The disadvantage of estno gauge is low bystrodeystvie- and its complexity, since in each measuring channel occurs repeatedly generating and therefore increases the measurement time. The purpose of the invention is to increase the speed and simplify the device. The goal is achieved by the fact that the ultrasonic thickness gauge is equipped with the first trigger, the first input of which is connected to the output of the probe channel generator of the reference channel,. and the second input - with the receiving converter of the reference channel, the second trigger, whose two inputs are connected to the receiving converters of the measuring channels, two generators .91

standard frequencies, the inputs of which are connected to the first output of the control unit, the second output of which is connected to the input of the generator of sounding pulses of the reference channel, the first And circuit, the first input of which is connected to the output of the generator of sounding pulses of the reference channel, the second input - to the output of the first trigger, and the output is with the input of the first counter, the second And circuit connected between the second trigger and the counter connected in parallel with each other and connected to the second input of the second And circuit, null organ, input cat The op is connected to the output of the third counter, and a rewrite unit whose input is connected to the output of the first counter, and the output to the second input of the third counter, the second input of the third counter is connected to the output of the first standard frequency generator, and the input of the probe pulse generator is connected to the receiving converter of the reference channel.

The drawing shows a block diagram of an ultrasonic thickness gauge.

The thickness gauge contains a reference channel consisting of a series-connected probe pulse generator 1, an emitting transducer 2 and a receiving transducer 3 The first measuring channel consists of the emitting transducer and and. receiving transducer 5; Second measuring channel consists of radiating transducer 6 and receiving transducer 1; Generator output of 8 probe pulses is connected to radiating transducers and 6.

In addition, the thickness gauge contains the first trigger 9, the first input of which is connected to the output of the generator 1 of probe pulses, and the second input to the receiving transducer 3, the second trigger 10, two inputs of which are connected to the receiving transducer 5 and 7, two generators 11 and 12 standard frequencies whose inputs are connected to the first output of the control unit 13, the second output of which is connected to the input of the probe pulses generator 1, the first circuit 1 AND, the first input of which is connected to the output of the generator | a 1, the second input - with the output of the first trigger 9, and the output - with the input of the first counter 15, the second circuit 16 And connected between the second trigger 10. and the second

1554

the counter 17 is connected in parallel with each other and connected to the second input of the second circuit 16 And, the null body 18, the vrd of which is connected to the output of the third counter 19, and the rewriting unit 20, the input of which is connected to the output of the first counter 15, and the output to the second the input of the third counter 19. The third input of the third counter ka 19 is connected to the output of the first generator 11 of the standard frequency, and the generator input 8 of the probe pulses is connected to the receiving transducer 3. The thickness gauge contains

5 is also a reflector 21.

The thickness gauge works as follows.

The control unit 13 starts the probe pulse generator 1 of the etaq channel channel and the generators 11 and 12 of the standard frequency, which produce pulses whose following frequencies are equal to f and ffj, respectively. A generator of probed pulses triggers a radiating transducer 2, an ultrasonic pulse from which, reflected from the surface of the reflector 21, is received by the receiving transducer 3. At the same time, the signal from generator 1 is fed to the single input of the transducer 9, the output of which appears is a single signal that opens 1 M circuit, and the pulses from the generator 12 will start to flow to the counter 15, which counts them. The signal from the receiving converter 3 will go to the zero input trigger of 9, which is transferred to the zero state and closed The circuit 1f AND, and the pulse counting by the counter 15 stops. In counter 15, the number N / will be fixed; proportional to the reference distance

N,,. {,,

5 where f is the propagation time of the ultrasonic pulse in the reference channel; C- - propagation speed

Claims (2)

ultrasound in the air. 0 The number N will be written by block 20 overwriting into counter 19, which works for subtraction. This number will be read by pulses from generator 11, the next with frequency g. When the $ 1 counter counts down to zero, the zero-body 18 will issue a signal to the circuit 16 AND and the rewriting block 20, which will again write the number from the counter 15 to the counter5 of the 19, etc. Thus, from the output of the zero-body 18 to the input of the circuit 16 will receive pulses, the next with frequency h. X - - l where 1 is the time for which the number N is read in the counter 19 to zero. The signal from the receiving transducer l 3 is fed to the input of the generator 8 probe pulses, which will start the emitting transducers 4 6. Ultrasonic pulses reflected from the surfaces of the product and the support are received by the receiving transducers 5 and 7- The emitting and receiving transducers kJ are installed at the same distance nii ij from the support. The signal from the receiving converter will go to unit trigger 10, the output of which will receive a signal that goes to input 16 I. The signal from the receiving converter 7 will go to the zero input of the trigger and transfer it to the zero state and close circuit 1b I. Thus, the scheme; 16 And will be open during the time to the bulk thickness of the product (y), i the time of propagation of ultrasonic vibrations to the surfaces of the support and the product, respectively; 1, -1 distances to the surfaces of the support and the product, respectively. Substituting the value of frequency l from formula (.2) into formula 3, we obtain W.% .-, from where Vr In order for the number NX to express the distance in mm, it is necessary that where Cj is taken in mm. 5 Thus, the counter 17 shows the thickness of the products. The use of the invention makes it possible to increase the fast response of the device and simplify it due to the one-time generation of ultrasonic pulses in the measuring channels. The invention of the Ultrasonic Thickness Gauge, containing a reference channel consisting of a series-connected probe pulse generator, an emitting and receiving transducer, two measuring channels, each of which consists of an emitting and receiving transducer, a probe pulse generator, the output of which is connected to the emitting transducer measuring channels, three counters, a control unit and a reflector, characterized by the fact that, in order to increase speed and simplify the device, it provides the first trigger, the first input of which is connected to the output of the generator of the probe pulses of the reference channel, and the second input - with the receiving converter of the reference channel, the second trigger; two inputs of which are connected to the receiving transducer of measuring channels, two generators of standard frequency, the inputs of which are connected to the pe output; control unit, the second output of which is connected to the input of the probe pulse generator of the reference channel, the first circuit AND, the first input of which is connected to the output of the probe channel generator of the reference channel, the second input to the output of the first trigger, and the output to the input of the first counter, second circuit And connected between the second trigger and the counter, connected in parallel to each other and connected to the second input of the second circuit AND, a null body whose input is connected to the output of the third counter, and the rewriting unit, input D which is connected to the output of the first counter, and the output to the second input of the third counter, the second input of the third counter is connected to the output of the first standard frequency generator, and the input of the probe generator is connected to the receiving converter of the reference channel. Information sources. 9 X / g tr t j BO accepted attention during examination 5 1, Copyright certificate CttP tr 384005, cl. G 01 B 17/02, 1969. 2. USSR author's certificate for application No. 2603701/28, -....,,, cl. G 01 B 17/02, 1978 (prototype).