SU838575A1 - Ultrasonic flow rate fluctuation meter - Google Patents

Description

 . one

This invention relates to acoustic measurements and can be used in various fields of folk economy to measure flow rate fluctuations.

Ultrasonic flow velocity meters are known that contain a probe pulse generator, piezoelectric transducers included in a synchro-ring circuit, and a recording unit l.

However, these devices have insufficient speed, which limits the ability to measure flow rate fluctuations.

The closest to the invention in its technical essence is an ultrasonic flow velocity fluctuation meter containing two reversible electroacoustic transducers, a transmitter and a receiver, connected through the first and second controllable keys with electroacoustic transducers, a time-to-digital converter, a unit for calculating inverse values, a subtracting unit and a synchronizer connected to the receiver by the transmitter, time-to-digital converter and control inputs of the keys 2.

The disadvantage of this device is the limited accuracy of measurements when working with fluctuating flows, since the device produces discrete values of measured flow velocity longer than the pulse repetition period when emitted against the direction of flow.

The purpose of the invention is to improve the accuracy of measurements.

This goal is achieved by inserting the first and second adders, a reference digit block, a third key, a switch, a digital-5 analog converter and a differentiating chain, one of the inputs of the first adder is connected to the output of the time-digital converter connected to the first input switch, the second input of the first adder is connected via the third key to the output of the block of the reference figure, and the output of the first adder is connected to the second input of the switch, the output

5 which is connected to the input of the second adder through a return value calculator and a subtracting unit, the output of which is connected to the output of the device through the analog-digital converter and differentiated circuit, while the control inputs of the first adder, switch and the third key are connected to the synchronizer outputs.

The drawing shows a structural diagram of the proposed ultrasonic meter fluctuations in flow velocity.

The device contains two reversible electroacoustic transducers 1 and 2, a transmitter 3, a receiver 4, a synchronizer 5 connecting, for example, pulse generators and delay circuits, a time interval interval digit converter, the adder 7, a reference digit unit 8, a return calculation unit 9 , subtractor, block 10, adder 11, digital-analogue converter 12, differentiation chain 13, keys 14-16 and switch 17

Electro-acoustic transducer 1 is connected to the first output of transmitter 3 and, via key 14, to electro-acoustic transducer 2, which is connected via key 15 to receiver input 4. Receiver 4 output is connected to synchronizer input 5. Second transmitter output 3 is connected to transmitter start input 6 type time interval-digit, the control input of which is connected to the output of the synchronizer 5. The other output of the synchronizer 5 is connected to the start input of the transmitter 3. The output of the converter is of the type time interval-digit connection It is connected with the first inputs of the adder 7 and the switch 17, and the output of the adder 7 is connected to the second input of the switch 17. The second input of the adder 7 is connected via switch 16 to the output of the reference figure block 8. The control inputs of the adder 7, the block 9 for calculating the return values, the keys 14-16 and the switch 17 are connected to the corresponding outputs of the synchronizer 5. The output of the switch 17 is connected to the input of the block 9 for calculating the return values, the output of which is connected to the input of the subtracting block 10, and its output through an adder 11, a digital-to-analog converter 12 and a differentiating chain 13 are connected to the output terminal of the device. The output of the sign of the subtractive unit 10 is connected to the input of the sign of the adder 11.

The ultrasonic flow velocity fluctuation meter works as follows. .

The measurement is performed in two modes, and the transition from one mode to another is carried out automatically using synchronizer 5.

In the first mode in the initial state, the key 14 is closed, the keys 15 and 16 are open. In the switch 17, the output terminals of the converter 6 are of the type time interval-digit and the input of the block 9 for calculating return values. In momen

time t pulse coming from the third output of the synchronizer 5, the transmitter 3 is started, the output of which forms the excitation pulse of the electroacoustic transducers 1 and 2. This pulse arrives at the electroacoustic transducer 1 and through the key 14 to the electroacoustic transducer 2 1 and 2 emit probing acoustic pulses directed along and against the direction of the stream of interest. At the same time, the output pulse of the transmitter 3 starts the transducer 6 of the time type

5 interval-digit. After the probe pulses are emitted by a pulse coming from the second output of the synchronizer 5, the key 15 Зс1 closes. An acoustic pulse is received by the electroacoustic transducer 2, the base distance d passing between the electroacoustic transducers 1 and 2 is passed in the direction of flow. The pulse is through the switch 15 and the receiver 4 is fed to the input of the synchronizer 5. Similarly, an acoustic pulse is transmitted that passes against the direction of flow and from the electroacoustic transducer 1 through the keys

l 14 and 15 and receiver 4 goes to

the synchronizer input 5. A pulse, which comes from the fifth output of the synchronizer 5, records the digital values of the output of the time-to-digital converter type 6 to the registers of the adder 7. The registers of the return calculation unit 9 are recorded in a digital value by a pulse coming from the output of synchronizer 5. After the recording is finished, the pulse coming from the fourth output of synchronizer 5 resets and prepares the converter for type 6 time interval-digit. Simultaneously impulse arriving

5 from the eighth output of the synchronizer 5, the block 9 calculates the reciprocals. After the termination of the calculation, the digital quantity expressed by the formula

C-VACO.cC

S

AO

where C is the ultrasound velocity in the test stream; V. is the average variable speed V (t) of the flow under study over the time interval TD;

Claims (2)

oL is the angle between the base d and the velocity vector of the flow studied. After the digital value 1 / Md is written to the registers of the subtracting unit 10 by a pulse coming from the eighth output of the synchronizer 5, the block 9 is reset and prepared. At the same time, the pulse coming from the seventh output of the synchronizer 5 switches the switch 17 to the closing state of the input of block 9 calculating the reciprocals and the output of the adder 7. Next, the pulse coming from the eighth output of the synchronizer .5 starts block 9, and a digital value is written to its registers from the output of the adder 7. After the calculation is completed, 9 ke pulse synchronizer 5 adder 7 is reset and the input of the subtractor unit 10 by steps digital value vyrazhaema formula - j3; Vecos4. where VP is the average value of the variable velocity V (t) of the flow under study over the time interval of Guvo. After the termination of writing .digitra l / Np to the registers of the subtracting unit 10, the sequential embossing by the algorithm exists. In the flow of liquids, i.e. digital difference value p., after calculating the difference digital value P, it is written to the registrar 11, operating according to the NV --- UK algorithm, -, io where 11 is the output value of the adder 11, is the constant coefficient, the value of which is determined by the pulse coming from the output-sign of the subtracting device 10. In the adder it is initially set d / 2 С o S (; 1/2,.., n -d / cos ot.Thus, digital output is generated at the output of the adder 11 the value according to (3) and (4) is equal to. The device operation in the first mode is completed by automatic reset. According to expression (3), after completing work in the first mode, the l / Ngror register of the second one is written to the first register register of the first addendum register of the second addendum. and prepared, converter 6 prepared, adder 7 reset and prepared, block 9 for calculating return values prepared, switch 17 in the closure mode of block 9 input and output of adder 7, keys 14 and 15 are closed, key 16 is open t. After the end of operation of the device 1 in the first mode, the pulse arriving from the first output of synchronizer 5, the key 14 opens and the device begins to work in the second mode. In this mode, the transmitter 3 is periodically triggered by pulses coming from the third output of the synchronizer 5, and the period T of the repetition of the starting pulses is set to - T%. The acoustic pulses are radiated in the direction of flow, are received by the electro-acoustic transducer 2, and through the switch 15 and the receiver 4 periodically arrive at the input of the synchronizer 5, the transducer 6 is started by the output pulse of the transmitter 3 and is stopped by the pulse from the fourth output of the synchronizer 5 and the digital value is recorded in adder 7. After each arrival of the digital value at the output of the adder 7 of the synchronizer 5 pulse, coming from its eighth output, the blot is started 9. After the end The calculation in block 9 periodically generates a digital value at its output, which is written to the register of the second addend of the subtracting block 10, after which block 9 is reset and prepared by synchronizer pulse 5. . In the proposed device, the output value is the time dependence of the voltage, proportional to the average, over the averaging period T, the deviation of the measured flow rate from its mean market value 7 (t). Thus, for the first time, the device provides the possibilities of ultrasonic measurement of fluctuations of a variable flow velocity, the fluctuation period of which is much less than the time it takes for an acoustic pulse of a base distance d in the flow direction. Claims of the invention Ultrasonic flow rate fluctuation meter containing two reversible electroacoustic transducers, a transmitter and a receiver. connected through the first and second controlled keys with electroacoustic transducers, a time-to-digital converter and control inputs of the keys, which is u and u with. By the fact that, in order to improve measurement accuracy, the first and second adders, a reference digit block, a third key, a switch, a digital-to-analog converter and a differentiating chain are entered into it, one of the inputs of the first adder is connected to the output of the time interval-digit converter connected to the first the input of the switch, the second input of the first adder is connected via the third key to the output of the block of the reference digit, and the output of the first accumulator is connected to the second input of the switch, the output of which is through the calculator values and subtractive unit is connected to the input of the second adder, the output of which is connected to the output of the device through an analog-digital converter and a differentiating chain, while the control inputs of the first adder, switch and third key are connected to the synchronizer outputs Sources of information taken into account in the examination 1, USSR Author's Certificate No. 526827, Cl, G 01 P 5/00, 1976. 2. The patent of Germany No. 2431346, cl. G 01 P 5/00, 1976.