KR20100007215A - Ultrasonic transducer control method of a ultrasonic flowmeter and ultrasonic flowmeter to applying the method - Google Patents

Abstract

PURPOSE: An ultrasonic transducer control method of an ultrasonic flowmeter and the ultrasonic flowmeter in which the method is applied are provided to improve the precision of the flow measurement by minimizing the delay time due to the electromagnetic wave loss. CONSTITUTION: An ultrasonic transducer control method of an ultrasonic flowmeter comprises a flow rate measuring part(1), ultrasonic transducers(2,3), a driver circuit(4), a reception detection circuit(6), a switching circuit(5) and a controller(7). A fluid to be measured flows in the flow rate measuring part. The ultrasonic transducer is arranged to be corresponding to the flow rate measuring part and transmits ultrasonic wave. The driver circuit drives the ultrasonic transducer. The reception detection circuit detects a signal from the ultrasonic transducer. The switching circuit interlinks the ultrasonic transducer to the driver circuit and the reception detection circuit. The controller controls the operation of the switching circuit and driver circuit.

Description

Ultrasonic transducer control method of a ultrasonic flowmeter and Ultrasonic flowmeter to applying the method

The present invention relates to a control method of an ultrasonic transducer constituting an ultrasonic flowmeter of the propagation time difference method, and an ultrasonic flowmeter to which such a method is applied.

As is well known, various types of flowmeters for measuring the flow rate of a fluid such as a liquid or a gas have been developed, such as a differential flow meter, an area flow meter, an electromagnetic flow meter, an ultrasonic flow meter, a turbine flow meter, a volumetric flow meter, a vortex flow meter, and the like. It is already widely used.

Among these, the ultrasonic flowmeter is a flowmeter of a method of radiating ultrasonic waves from the outside of the pipe and receiving a transmission wave or a reflected wave that changes depending on the flow rate outside the pipe to obtain a flow rate. Are distinguished.

In the case of the propagation time difference method, in consideration of the fact that the speed at which the ultrasonic wave passes through the fluid has a constant relationship with the average flow rate, the ultrasonic passage time is measured, and then the flow rate is determined in consideration of the flow rate and the diameter of the tube.

1 illustrates an example of an ultrasonic flow meter of a propagation time difference method, which will be described below with reference to the related art.

As illustrated in FIG. 1, the ultrasonic flowmeter is disposed so as to face each other in a flow rate measuring unit 1 through which a fluid to be measured flows, and a pair of ultrasonic transducers 2 and 3 which transmit and receive ultrasonic waves. ), A drive circuit 4 for driving the ultrasonic transducers 2 and 3, a reception detection circuit 6 for detecting a received signal from the ultrasonic transducers 2 and 3, and a pair of ultrasonic transducers. A switching circuit 5 which switches (2, 3) to the driving circuit 4 and the reception detecting circuit 6, respectively, and controls the operation of the driving circuit 4 and the switching circuit 5, and receives the receiving detecting circuit. A control unit 7 which receives the detection signal from (6) and calculates the flow rate is formed.

In the operation of the ultrasonic flowmeter, first, when a transmission start signal is input from the control unit 7 to the drive circuit 4 while the measurement fluid is flowing inside the flow rate measuring unit 1, the drive circuit 4 controls the control unit. Driven by the transmission start signal from (7) and outputs a predetermined electrical transmission pulse to the second ultrasonic transducer 3 through the switching circuit 5, and the electrical transmission pulse from the driving circuit 4 is When input to the second ultrasonic transducer 3, the second ultrasonic transducer 3 is driven by an electrical transmission pulse from the drive circuit 4, thereby physically transmitting a physical vibration ultrasonic pulse corresponding to the transmission pulse to the outside. Will print. The physical vibration ultrasonic pulses output from the second ultrasonic transducer 3 and propagated into the flow rate measuring unit 1 are received by the first ultrasonic transducer 2, and the first ultrasonic transducer 2 is external. The physical vibration ultrasonic pulse received from is converted into an electrical reception pulse and output to the reception detection circuit 6 through the switching circuit 5. The reception detection circuit 6 receives a reception pulse from the first ultrasonic transducer 2, determines a reception timing, and outputs the reception timing to the controller 7. The control unit 7 measures the propagation time " t1 " from the time when the transmission start signal is output to the drive circuit 4 to the time when the output signal (reception detection signal) from the reception detection circuit 6 is input.

Thereafter, the switching circuit 5 is switched by the controller 7 so that the driving circuit 4 and the first ultrasonic transducer 2 are electrically connected to each other, and the reception detecting circuit 6 and the second ultrasonic transformer are connected. The producers 2 are electrically connected to each other. In this state, when the transmission start signal is output from the control unit 7, the first ultrasonic transducer 2 is driven by an electrical transmission pulse from the driving circuit 4 to correspond to the physical vibration ultrasonic wave corresponding to the transmission pulse. The pulse is output to the outside, and the physical vibration ultrasonic pulse output from the first ultrasonic transducer 2 and propagated into the flow rate measuring unit 1 is received by the second ultrasonic transducer 3 and the control unit 7 ) Measures the propagation time "t2" from the time point at which the transmission start signal is output to the drive circuit 4 to the time point at which the output signal (receive detection signal) from the reception detection circuit 6 is input.

Subsequently, the propagation time t1 when the control unit 7 propagates the physical vibration ultrasonic pulse from the second ultrasonic transducer 3 to the first ultrasonic transducer 2 and the first ultrasonic transducer ( Propagation time t2 at the time of propagating the physically vibrating ultrasonic pulse from 2) to the second ultrasonic transducer 3 and the surrounding environment elements (for example, the first ultrasonic transducer 2 and the second ultrasonic transducer). The flow rate of the measurement fluid V, taking into account the distance L between the producers 3, the sound velocity C of the measurement fluid, the angle between the flow direction of the measurement fluid and the center of the ultrasonic transducers 2, 3, etc. ) Is calculated and the flow rate Q of the measurement fluid is calculated based on the flow rate V of the measurement fluid and the cross-sectional area S of the flow rate measuring unit 1.

On the other hand, in the prior art, the driving circuit 4 has a method of outputting a transmission pulse of a constant voltage, as shown in Fig. 2 (a), the period (c) of the transmission pulse is a corresponding ultrasonic transformer The resonant periods of the producers 2 and 3 are applied. In this case, the reception pulses of the ultrasonic transducers 2 and 3 are shaped as shown in FIG. 2B due to the loss in the propagation process.

The reception detection circuit 6 receives a reception pulse as shown in (b) of FIG. 2 from the ultrasonic transducers 2 and 3 and receives a reception detection signal when the reception pulse of the reference voltage V1 or more is detected. It outputs to the control part 7.

However, according to the related art, a method for reducing the delay time T1 until the reception pulse of the reference voltage V1 or more is detected cannot be taken, and thus the propagation time t1 and t2 due to the delay time T1. ) Error is enlarged, and this causes a problem that the reliability of the measured flow rate is lowered.

For reference, as the delay time T1 is longer, the measurement propagation times t1 and t2 are inevitably longer than the actual propagation time, so the measured flow rate value is calculated in proportion to the delay time T1 rather than the actual flow rate value. It can only grow.

The present invention has been invented to solve the problems according to the prior art as described above, to provide an ultrasonic transducer control method of the ultrasonic flowmeter to minimize the delay time due to propagation loss to improve the accuracy of the flow measurement. There is this.

It is also an object of the present invention to provide an ultrasonic flowmeter to which this method is applied.

In the ultrasonic transducer control method of the ultrasonic flowmeter for achieving the above object, in the ultrasonic transducer control method of the ultrasonic flowmeter for controlling the oscillation of the ultrasonic transducer by controlling the operation of the drive circuit in the control unit constituting the ultrasonic flowmeter By controlling the operation of the driving circuit via the control unit, the method is characterized in that for outputting the transmission pulse from the driving circuit to the ultrasonic transducer which is gradually increased in accordance with the resonant period of the ultrasonic transducer.

In addition, the ultrasonic flowmeter according to the present invention includes a flow rate measuring unit for flowing the fluid to be measured, a pair of ultrasonic transducers which are disposed to face each other and transmit and receive ultrasonic waves, and a drive circuit for driving the ultrasonic transducers; A reception detection circuit for detecting a received signal from the ultrasonic transducer, a switching circuit for switching a pair of ultrasonic transducers to the driving circuit and the reception detection circuit, respectively, and controlling the operation of the driving circuit and the switching circuit, and receiving An ultrasonic flowmeter having a control unit for calculating a flow rate by receiving a detection signal from a detection circuit, wherein the driving circuit is operated and controlled by the control unit, and outputs an electrical transmission pulse to an ultrasonic transducer through a switching circuit, wherein Is gradually increased and varied according to the resonant period of the ultrasonic transducer. It has a structure that.

According to the present invention, by controlling the operation of the drive circuit via a control unit, and takes a method of outputting a transmission pulse from the drive circuit to the ultrasonic transducer which is gradually increased in accordance with the resonant period of the ultrasonic transducer, Since the slope of the received pulse is increased and the delay time is reduced, the propagation time is closer to actual than the conventional method, and the error of the measured flow rate value calculated on the basis is greatly reduced, thereby greatly improving the accuracy of the flow measurement. There is.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, the ultrasonic transducer control method of the ultrasonic flowmeter according to the present invention, by controlling the operation of the drive circuit (4; FIG. 1) in the control unit (7; FIG. 1) constituting the ultrasonic flowmeter, the ultrasonic transducer (2, 3; see FIG. 1) to control the oscillation, but control the operation of the drive circuit 4 via the control unit 7, as shown in Fig. 3 (a), ultrasonic transducers (2, 3) It characterized in that the output pulse is gradually increased in accordance with the resonant period of from the drive circuit 4 to the ultrasonic transducer (3).

According to the present invention, as shown in (b) of FIG. 3, since the slope β of the reception pulses of the ultrasonic transducers 2 and 3 becomes large, the delay time T1 is reduced, and thus the propagation time t1. , t2) is closer to actual than in the prior art, and the error of the measured flow rate value calculated on the basis thereof is greatly reduced.

In the present embodiment, the ultrasonic transducer control method according to the present invention is applied to the ultrasonic flowmeter as shown in FIG. 1, but the ultrasonic transducer control method according to the present invention is not limited thereto and is already known or performed. Of course, it can be applied to all the time difference ultrasonic flowmeter.

Referring to Figure 1 and Figure 3 (a) will be described with respect to the ultrasonic flowmeter according to this embodiment to which the ultrasonic transducer control method is applied.

As shown in FIG. 1, the ultrasonic flowmeter according to the present embodiment includes a pair of ultrasonic waves disposed opposite to each other in the flow rate measuring unit 1 and the flow rate measuring unit 1 through which the fluid to be measured flows. The transducers 2 and 3, the drive circuit 4 for driving the ultrasonic transducers 2 and 3, the reception detection circuit 6 for detecting the received signal from the ultrasonic transducers 2 and 3, A switching circuit 5 for switching the pair of ultrasonic transducers 2 and 3 to the driving circuit 4 and the reception detecting circuit 6, respectively, and to operate the driving circuit 4 and the switching circuit 5, respectively. It forms a structure provided with the control part 7 which controls and calculates flow volume by receiving the detection signal from the reception detection circuit 6. As shown in FIG.

Here, in the case of the ultrasonic flowmeter according to the present embodiment, the driving circuit 4 is operated and controlled by the control unit 7 to transmit electrical transmission pulses to the ultrasonic transducers 2 and 3 through the switching circuit 5. It should be noted that the output pulse is characterized in that the transmission pulse is gradually increased and varied according to the resonant periods of the ultrasonic transducers 2 and 3.

In the present embodiment, the total voltage output amount of the transmission pulse of the drive circuit 4 is the same as the conventional method of outputting a constant voltage, and the period C is also the same as the conventional method of the ultrasonic transducers 2 and 3. In the state in which the resonance period was set, the transmission signals of the ultrasonic transducers 2 and 3 were determined so that the slope β of the received signals of the ultrasonic transducers 2 and 3 was as maximum as possible. The transmission signal of the ultrasonic transducers 2 and 3 is the slope of the received signal of the ultrasonic transducers 2 and 3 while changing the slope α and the initial voltage value of the ultrasonic transducers 2 and 3. ) Was taken as the maximum value, and the taken inclination α and the initial voltage value were set as the transmission signals of the ultrasonic transducers 2 and 3.

The present invention is not limited to the embodiment as described above, and of course, various modifications can be made without departing from the scope of the following claims.

1 is a view showing an example of an ultrasonic flow meter,

2 is a diagram illustrating a transmission and reception pulse according to the prior art;

3 is a diagram illustrating transmit and receive pulses according to the present invention.

-Explanation of terms for the main parts of the accompanying drawings-

One ; Flow measuring unit 2; First ultrasonic transducer,

3; Second ultrasonic transducer, 4; Drive circuit,

5; Switching circuits; Reception detection circuit,

7; Control unit.

Claims (2)

In the ultrasonic transducer control method of the ultrasonic flowmeter for controlling the oscillation of the ultrasonic transducers (2, 3) by controlling the operation of the drive circuit (4) in the control unit (7) constituting the ultrasonic flowmeter, By controlling the operation of the driving circuit 4 via the control unit 7, a transmission pulse gradually increasing according to the resonant periods of the ultrasonic transducers 2 and 3 is transmitted from the driving circuit 4 to the ultrasonic transducer 3. Ultrasonic transducer control method of the ultrasonic flowmeter to output. A flow rate measuring unit 1 through which the fluid to be measured flows, a pair of ultrasonic transducers 2 and 3 disposed to face each other and transmitting and receiving ultrasonic waves, and ultrasonic transducers 2 and 3. A driving circuit 4 for driving a circuit, a reception detecting circuit 6 for detecting a received signal from the ultrasonic transducers 2 and 3, and a pair of ultrasonic transducers 2 and 3, respectively. ) And a switching circuit 5 for switching to the reception detecting circuit 6 and controlling the operation of the driving circuit 4 and the switching circuit 5, receiving a detection signal from the reception detecting circuit 6, In the ultrasonic flowmeter with a control unit 7 for calculating The driving circuit 4 is operationally controlled by the control unit 7 to output electrical transmission pulses to the ultrasonic transducers 2 and 3 through the switching circuit 5, wherein the transmission pulses are transmitted to the ultrasonic transducers 2, 3. Ultrasonic flow meter, characterized in that gradually increasing and variable according to the resonant period of 3).

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