RU9955U1 - VICHREACOUSTIC FLOW CONVERTER - Google Patents

Abstract

A vortex-acoustic flow transducer containing a measuring pipeline with a vortex transducer placed in it in the form of a flow body and a pair of ultrasonic transducer-receiver mounted on its surface located on opposite sides of the pipeline opposite each other and connected respectively to a signal generator and to a series-connected amplifier, phase detector and to a shaper of output signals, characterized in that a second pair of ultrasonic transducers is inserted into it the emitter-receiver located opposite each other on opposite sides of the pipeline on the same circle as the first pair, while the distance between the emitter and receiver of different pairs is less than between their emitters or receivers, the emitter of the second pair is connected to the signal generator, and the receiver through the second amplifier to the second input of the phase detector, the generator is a source of a continuous signal, and the measuring pipe is made with a confuser at its input and with a diffuser at the output.

Description

Vortex-acoustic flow transducer.

The utility model relates to means for measuring the volumetric flow rate of a liquid, namely, vortex flowmeters with a measurement of the phase shift of the propagation of ultrasonic waves and can be used in measurement technology to account for the flow of water in water and heat supply systems.

Known flow converter described in a.z. Japan No. 3-61892 Ultrasonic flowmeter according to class G01FI / 66, c. 05.20.83, op. 09/24/91.

The known flowmeter contains a measuring pipeline, several pairs of ultrasonic (ultrasound) transducers with the same length of the path of propagation of ultrasonic signals installed on the wall of the pipeline at a given angle to the path of the medium, a device for setting 2 signals of different frequencies, connected respectively to two transmitting ultrasonic transducers, generating ultrasonic signals of different frequencies, but of the same level and with leading edges following in the same phases, receiving ultrasonic converters connected through an amplifier Whether an adder associated with a device registration time achieving the result of summation of a set level, connected with the calculator by the flow rate

MKI-6: GOlFl / 32, 1/66

the time period from the receipt of the leading edge of the ultrasonic signals to the result of the summation of the set level.

A disadvantage of the known device is its complexity, due to the presence of several pairs of ultrasonic converters, their installation at a strictly defined angle (which is inconvenient in operation) by the formation of different frequencies, the need to register the time to reach the total signal at a certain level.

A vortex flowmeter is known as described in the DOS 4003 Specification of August 1993. The Fisher-Rosemount Model 8800 Intelligent Vortex Flowmeter is shown on page 4 for a diagram.

The known transducer contains a measuring pipe with a vortex transducer installed in it in the form of a plate with a small flexible part connected to a piezoelectric sensor connected to an electronic signal transducer, consisting of a series-connected anti-aliasing filter, an analog-to-digital transducer, a first galvanic isolation device, a digital a follow-up filter, a second galvanic isolation device and a pulse counter, while the digital follow-up filter with a microprocessor, one output of which is connected to an eight-digit display, the second output is with a digital-to-analog converter, and the third output is with a digital communication device connected to one of the microprocessor inputs.

A disadvantage of the known converter is that it cannot measure low flow rates at a low flow rate, t, k. the piezoelectric sensor responds to mechanical deformation of the flexible part of the plate, and this deformation at a low flow rate becomes very small. In addition, the signal processing system is very complex.

The closest in technical essence to the claimed is a vortex-acoustic flow transducer described in a.z. Japan th 3-12692 A method for detecting vortices and an ultrasonic vortex flowmeter according to class. G01F1 / 32, c. 02/14/83. , op. 02.20.91. and selected as a prototype.

The known vortex-acoustic transducer contains a measuring pipeline with a vortex transducer located in it in the form of a flow body — a trottol prism — and ultrasonic transducers mounted on its surface opposite each other — a radiator and a receiver, while the emitter is connected to an intermittent signal generator, and an amplifier is connected in series to the receiver , a phase detector, a filter and an operation unit generating output signals, while the detector output is connected to a circuit

forming a reference signal, the output of which is connected to the second input of the detector, and the input to the intermittent signal generator. A disadvantage of the known device is the unsatisfactory measurement accuracy due to the operating principle underlying the design, namely, firstly, using a discrete (discontinuous) signal for radiation, and secondly, obtaining a useful signal as the phase difference between the reference and the signal from the pair Ultrasound transducers are a transmitter-receiver, one of which (reference) does not depend on pipeline vibration, pressure and temperature fluctuations, and the second (from the output of the ultrasound receiver) depends, and as a result, a useful signal is also ISITO from pipeline vibrations, fluctuational ation pressures and temperatures, which deteriorates the accuracy of {Measurements.

The purpose of the claimed utility model is to increase the accuracy of measurements.

This goal is achieved by the fact that in a vortex-acoustic flow transducer containing a measuring pipe with a vortex transducer placed in it in the form of a flow body and a pair of ultrasonic transducers mounted on its surface: radiator-receiver transducers located opposite each other and connected to the signal generator and to the amplifier connected in series , to the phase detector, filter, and output driver, according to a utility model, a second pair of ultrasound

converters emitter-receiver located opposite the other side of the pipeline on the same circumference as the first pair, the distance between the I-emitter and the receiver of different pairs is less than between their emitters or receivers, the emitter of the second pair is connected to the generator signal, and the receiver through the second amplifier - to the second input of the phase detector, the generator is a source of a continuous signal, and the measuring pipe is made with a confuser - at its input and a diffuser - at the output the second part.

The introduction into the device of a second pair of ultrasonic transducers emitter - receiver, located at the same circumference as the first pair, and at a distance by the emitter and receiver of different pairs, less than between their emitters or receivers, allows you to more accurately capture the resulting vortices and use as a useful signal, the phase difference between} signals of the receivers of the first and second pair. At the same time, since external factors, such as vibration of the pipeline, fluctuations in temperature and fluid pressure, affect both the signals received by both receivers, the effect of these factors does not affect the useful signal, which, combined with the use of a radiated continuous signal, increases measurement accuracy and allows you to accurately determine the flow. The presence of a confuser at the inlet and a diffuser at the outlet of the measuring pipeline, acting as jets straight, provides an averaging of the flow rate and increases the accuracy of flow measurement.

The inventive utility model has a novelty in comparison with prototypes, although it differs from it by the presence of such significant distinguishing features as a second pair of ultrasonic transducer-receiver, located on the same circumference of the pipeline surface as the first pair, and at a distance of the transmitter and receiver of different pairs less than between the emitters or receivers of these pairs, the implementation of the generator as a source of continuous signal, the implementation of the measuring pipeline with a confuser and a diffuser on its con ah.

The inventive eddyacoustic flow transducer can be widely used in measurement technology and therefore meets the criterion of industrial applicability. The inventive utility model is illustrated by drawings, which are presented on:

- FIG. {- general scheme of the vortex-acoustic flow transducer; FIG. 2 is a layout of two pairs of ultrasonic transducers of the transmitter and receiver in the vicinity of the pipeline.

The vortex-acoustic flow transducer contains a measuring pipeline with a confuser at its inlet and a diffuser at its outlet and with a vortex transducer placed in it in the form of a flow body and two pairs of ultrasonic transducers emitter-receiver mounted on its surface on one circle. The emitter and receiver of each pair are located on opposite sides of the pipeline opposite each other, while the distance between the emitter and receiver of different pairs is less than the distance between the emitters or receivers of these pairs. The emitters are connected to a continuous signal generator, and the receivers, through the first and second amplifiers, are respectively connected to two inputs of a phase detector connected to a filter, the output of which is connected to the INPUT} of the output signal shaper.

The vortex-acoustic flow transducer (see drawings) contains a vortex transducer K located at the liquid inlet inside the measuring pipe 2, on the outside: on the external surface of which there are two pairs of ultrasonic transducers 3, 3, and 4 at the same circumference. 4 i, two of which (3, 3 And) are emitters and are connected to an alternating voltage generator 5, and two (4 1, 4 II) are receivers, and the distance between each of the 3 L 3 1 emitters or receivers 41, 4 is less, than the distance between emitters 3 and 3 or receivers 4, while the receivers 41 and 4 I are connected respectively through amplifiers 6 I, 6 ii to a phase detector 7, the output of which is connected to the input of the filter 8, the output connected to the shaper 9 of the output signals. A confuser 10 is filled at the inlet of the measuring pipeline, and a diffuser 1 at its output.

The designation and implementation of the units and elements of the flow converter is then thin.

The vortex generator 1 is intended for the formation of vortices in the fluid flow and is a trapezoidal prism mounted wide to the liquid.

The measuring pipeline 2 is for providing a fluid flow and measuring its flow rate and is a pipe with a diameter of 32 to 200 mm.

Ultrasound: new transducers 3 and emitters - are designed to convert the alternating voltage of the generator into ultrasounds}. Oscillations, and U3 transducers 4. 4 i - receivers - for converting ultrasonic vibrations into an electrical signal, and are piezoelectric elements (see EG1-4D-21-20-ODO.339-180 TU / TsTS-19).

The generator 5 serves to generate a signal to be converted into ultrasonic vibrations; as it can be used, in particular, the generator of the microcontroller TR87S51GA (see the catalog of the company InteH). Frequency stability is provided by a 12 MHz quartz resonator. The signal is removed from the output A E already at a frequency of 1 MHz and through the D-trigger (the resonator and the trigger are not shown in the drawing) is supplied to the emitters and already with a shift of 180. Amplifiers 61.61 are used to amplify the signals and are made on two

5449D2A operational amplifiers that filter out interference and extract the difference frequency (see the book by A. Bulychev et al. Analog and Integrated Circuits. Handbook, 2nd ed., Minsk, Belarus, 1993, p. 220).

The phase detector 7 selects the difference frequency from the receivers 4 I, 411 of the first and second pairs of ultrasonic converters and is executed on I554TB9 triggers (see Logic integrated circuits КР1533, КР1544. Reference, Binom LLP, 993 or Radio Journal, 1995. , NQ 9, p. 6 D), which transform the phase model into a pulse width.

Adaptive filter 8 serves to filter random components from the phase detector / and real: 5ova5 {software on the aforementioned microconfolter TP87C51FA. Filfaiiya is carried out according to the algorithm for K1 X X - K2 X At p. Where X is the measured value of the period, and K1 and K2 are the coefficients, the choice of which is carried out using jumpers.

The output signal shaper 9 is also implemented on the TPo7C5 FA microcontroller. Nmpulsk formed by the microcontroller are fed through an input signal repeater (not shown in the drawing). executed on the integrated circuit 1554TM2 (see Logical integrated circuits КР1533,. Reference book. Publishing house of Binom LLP,

nine

993 g.), Further on a transistor kayach made on the Frr3i02B transistor (see Transistors. Reference M, Radio and communications 1989, cip. 78).

The period of the output pulses is calculated programmatically: Thy Twh X K - P, where Twh is the period of the input signal, K is a constant coefficient that is set by the jumper, and f 1 is the correction for non-linearity in the region of small rash The duration of the output pulses is greater than or equal to 00 ms.

The confuser 10 and the diffuser J at the inlet si and the outlet of the measuring pipeline 2b play the role of a straightener jets to average the flow velocity m and represent.

The vortex-acoustic flow transducer operates in a lean manner.

The fluid flow, whose speed .-) increases due to the confuser at the inlet of the measuring pipe 2, is fed into the flow transducer. When a trapezoidal shape (vortex generator) flows around the prism, a fluid stream in the measuring pipe 2 forms a vortex track behind it, the vortex frequency in which is highly accurate proportional to the source velocity. Alternating voltage from the generator 5 is supplied to the ultrasonic transducers 3 i, 3 i (emitters) and is converted into ultrasonic vibrations. These oscillations are emitted by emitters 3, 3 into the fluid flow, where it interacts with the vortices and turns out to be modulated in phase. Further, they are received by ultrasonic transducers - receivers 4, 4 ii and converted into electrical vibrations, amplified by amplifiers 6, 6 and fed to the phase detector. Parasitic factors such as vibration of the pipeline, changes in temperature L1, L1 {the densities arising in the measuring pipeline 2, are compensated by the presence of two pairs of amplification: transmitter-receiver transducers.

The phase difference between the signals from the receivers 4 i. The fourth and fifth pairs are determined on the phase detector ii in the form of a voltage., The frequency and amplitude of which corresponds to the intensity and frequency of the vortices, from the output of the phase detector enters the microprocessor adaptive filter 8, where the random components of this signal are filtered. From the output of filter 8, the signal is transmitted to the driver of 9 bi-input signals, where it is converted into pulses with a frequency proportional to the liquid flow rate. In comparison with the prototype of the inventive eddyacoustic flow transducer has a higher measurement accuracy.

Authors / - Shmigora V.N.

 g

 Aksenov V.N.

Claims (1)

A vortex-acoustic flow transducer containing a measuring pipeline with a vortex transducer located in it in the form of a flow body and a pair of ultrasonic transducer-receiver mounted on its surface located on opposite sides of the pipeline opposite each other and connected respectively to a signal generator and to a series-connected amplifier, phase detector and to a shaper of output signals, characterized in that a second pair of ultrasonic transducers is inserted into it the emitter-receiver located opposite each other on opposite sides of the pipeline on the same circle as the first pair, while the distance between the emitter and the receiver of different pairs is less than between their emitters or receivers, the emitter of the second pair is connected to the signal generator, and the receiver through the second amplifier to the second input of the phase detector, the generator is a source of a continuous signal, and the measuring pipeline is made with a confuser at its input and with a diffuser at the output.