RU2106602C1 - Ultrasound flowmeter - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: flowmeter has preobing pulse generator, receiving and amplifying route 2, peak detect or 3, comparator 4, and signal strobing device 5. EFFECT: higher measurement results. 2 dwg

Description

 The invention relates to measuring equipment, in particular, to measuring instruments that perform the measurement of fluid flow using ultrasound.

 The closest analogue of the invention is a non-contact ultrasonic water flow meter UZR-MP [1].

 This flow meter contains a block for receiving and generating signals. The structure of this unit includes a receiving-amplifying path, a probe pulse generator and a comparator.

 The indicated design of the flow meter allows a rather high accuracy of measuring the water flow with a relative error of about 2.0 - 2.5% with a total total weight of the secondary transducer of about 6.0 kg.

 Among the shortcomings of the considered design should include the influence of noise interference, also arising in the design of the device, on the reliability of the device with a possible increase in the level of these noises to the level of the useful signal.

 The technical result from the use of the invention is to reduce the influence of noise on the accuracy and reliability of the measurement of controlled parameters of the fluid flow.

 This is achieved by the fact that in the ultrasonic flow meter containing a signal reception and regeneration unit, which includes a receiving-amplifying path, a probe pulse generator and a comparator, a signal gating device and a peak detector are included in the receiving-amplifying path, and the output of the receiving-amplifying path connected directly to the first input of the peak detector, and to the second through a signal gating device, the second input of which is connected to the probe pulse generator, and the output is connected to the first input a comparator, the second input of which is connected to the output of the receiver-amplifier path, and the third to the output of the peak detector.

 In FIG. 1 shows a block diagram of a proposed technical solution; figure 2 - the shape of the received signals in time at the output of individual nodes of the block receiving and generating signals.

 The device for receiving and processing signals (BPiGS) contains a probe pulse generator (GZI) 1, a receiving amplifier circuit (PUT) 2, a peak detector (PD) 3, a comparator 4 and a signal strobe device (CSS) 5.

 In this case, the output 6 of the control panel 3 is connected to the inputs of the comparator 4, PD 3 and CSS 5, and the output 7 of the CSS 5 is connected to the inputs of the PD 3 and comparator 4. The output 8 of the PD 4 is connected to the second input of the comparator 4.

 Block receiving and generating a signal operates as follows.

 The probe pulse generator 1 outputs to the flowmeter circuit, including the USS 5, high-frequency signals 9 with a frequency determined by calculation and depending on the diameter of the pipeline, in which the flow parameters of the moving fluid and the installation diagram of the electroacoustic transducers sending the probe signal on the pipeline are measured 10 into the pipeline and receiving this signal after passing through the stream for subsequent processing in the flowmeter circuit.

After a time interval
t = L / C - t,
Where
L is the distance between the electro-acoustic transducers mounted on the pipeline;
C is the speed of sound in the measured medium;
t is the time interval that enables the launch of the CSS 5 until the probing signal 10 passes through the measured stream to the BPiGS,
after the signal 9 is supplied from GZI 1, the CSS 5 starts up and the latter gives out a gating pulse 11, which, through output 7, goes to the inputs of the PD 3 and comparator 4 and thereby prepares them for operation.

 Before the arrival of the gate pulse 11, the inputs of the PD 3 and the comparator 4 are closed for any signals that occur in the circuit.

 After bringing the PD 3 and the comparator 4 to the operating mode, they receive the probe signal 10 returned to the measurement circuit and fed to their inputs directly from the output of the PUT 2 during the entire duration of the strobe pulse 11, and process it as follows.

At the output of the PD 3, a constant signal 12 is formed, equal to
U _p.p. = K • U _max ,
Where
U _p.p. - constant voltage at the output of PD 3;
K is a constant coefficient selected within the limits depending on the degree of distortion of the signal received by the BPiGS;
U _{max the} maximum value of the probe signal 10, returned to the measurement circuit.

Moreover, the ratio U _max / U _p.p. for a particular flowmeter is kept constant. As a result, two signals arrive at comparator 4:
sounding signal 10 at the input of the receiving path,
constant signal 12
The excess of the probe signal 10 over the constant signal 12 allows the comparator 4 to provide reliable calculation of the parameters of the measured fluid flow, and closing the inputs of the PD 3 and the comparator 4 after the termination of the gate pulse 11 eliminates the influence of the increase in noise interference in the flowmeter circuit on the accuracy and reliability of its measurements.

Claims (1)

 An ultrasonic flow meter containing a signal receiving and generating unit, which includes a probe pulse generator, a receiving-amplifying path and a comparator, characterized in that the receiving-amplifying path is equipped with a signal gating device and a peak detector, wherein the output of the receiving-amplifying path is connected to the first the input of the peak detector directly, and with the second through the signal gating device, the second input of which is connected to the output of the probe pulse generator, and the output to the first input m of a comparator, the second input of which is connected to the output of the receiver-amplifier path, and the third to the output of the peak detector.

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