JPH04291114A - Vortex flowmeter - Google Patents

Abstract

PURPOSE:To continuously carry on flow rate measurement with a vortex flowmeter provided with two sets of ultrasonic sensors by effectively coping with abnormality when the abnormality occurs in one ultrasonic receiver. CONSTITUTION:When an abnormality detect signal is outputted from a sensor abnormality monitor circuit 12, a signal switching circuit 14 discontinues the fetching of detect signals from the receiver 6 of an ultrasonic sensor 3 in which the abnormality occurs and outputs a drive signal for driving the transmitter 7 of another normally operating ultrasonic sensor 4 to a phase comparator 16. The comparator 16 finds the phase difference between the drive signal and a detect signal fetched from the receiver 8 of the sensor 4 by comparison and detects the occurring period of Karman vortexes from the phase difference.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vortex flowmeter capable of efficiently measuring flow velocity using two sets of ultrasonic sensors.

0002

[Prior Art] Conventionally, this type of vortex flow meter has a vortex generation column for generating Karman vortices in a flow path through which fluid flows, and an ultrasonic transmitter and an ultrasonic wave generator are installed downstream of this vortex generation column. Some devices are equipped with two sets of ultrasonic sensors each consisting of a sonic receiver, and the fluid velocity is detected by determining the phase difference between the detection signals output from the two sets of ultrasonic sensors. It is something. The reason why two sets of ultrasonic sensors each consisting of an ultrasonic transmitter and an ultrasonic receiver are provided in this vortex flowmeter is to eliminate the influence of sudden changes in the temperature of the fluid. In other words, since the temperature change of the fluid affects each of these two sets of ultrasonic sensors, when calculating the phase difference,
These temperature effects are canceled out, and as a result, the effects of sudden changes in fluid temperature can be eliminated.

0003

[Problems to be Solved by the Invention] In the vortex flowmeter configured as described above, it is possible to detect the flow rate by determining the phase difference between the detection signals output from the ultrasonic receivers of two sets of ultrasonic sensors. Since it is designed to detect speed, for example, if an abnormality occurs in the ultrasonic receiver of one of the ultrasonic sensors, there is a problem that the flow rate may be measured incorrectly or the measurement itself may not be possible.

[0004] The present invention has been made in view of the above-mentioned circumstances, and is capable of effectively dealing with an abnormality in one of the ultrasonic receivers and allowing flow rate measurement to continue. The purpose is to provide a vortex flow meter that can

[0005]

[Means for Solving the Problems] In order to achieve the above object, the vortex flowmeter according to the first claim provides a vortex generation column in a pipe, and a superstructure comprising a transmitter and a receiver. In the vortex flowmeter, the Karman vortex generated in the vortex generation column is detected using two sets of sonic sensors, and the fluid velocity in the pipe is measured based on the detection signals of these ultrasonic sensors. Based on a transmitter that outputs a drive signal to drive each transmitter of the sensor and a detection signal output from a receiver of the ultrasonic sensor, the cycle of Karman vortex generation is detected, and the fluid velocity is calculated from this cycle. A phase comparator is provided between the ultrasonic sensor and the phase comparator to selectively compare the phases of a drive signal that drives the transmitter of the ultrasonic sensor and a detection signal output from the receiver. a sensor abnormality monitoring circuit that monitors the output abnormality of the receiver and outputs an abnormality detection signal when an output abnormality occurs; When the abnormality detection signal is not output from the monitoring circuit, the detection signal output from the receiver of the ultrasonic sensor is taken into the phase comparator, and when the abnormality detection signal is output from the sensor abnormality monitoring circuit, the phase The present invention is characterized in that the comparator stops receiving a detection signal from a receiver in which an abnormality has occurred, and a drive signal for driving an transmitter of an ultrasonic sensor is taken into the phase comparator.

In the vortex flow meter according to the second claim, a vortex generating column is provided in the pipe, and two sets of ultrasonic sensors each consisting of a transmitter and a receiver are used to detect the vortex generated by the vortex generating column. In a vortex flowmeter that detects the occurrence of a Karman vortex and measures the fluid velocity in a pipe based on the detection signals of these ultrasonic sensors, the position of the detection signal output from the receiver of these ultrasonic sensors is A phase comparator is installed between the ultrasonic sensor and the phase comparator, which detects the cycle of Karman vortex generation based on the phase difference and detects the fluid velocity from this cycle, and detects abnormal output of each receiver. and a sensor abnormality monitoring circuit for monitoring each, and each of the sensor abnormality monitoring circuits has a light emitter, and lights up the light emitter when detecting an output abnormality of the receiver of the ultrasonic sensor. That is.

In the vortex flowmeter according to the third aspect, a vortex generating column is provided in the pipe, and two sets of ultrasonic sensors each consisting of a transmitter and a receiver are used to detect the vortex generated by the vortex generating column. In a vortex flowmeter that detects the occurrence of a Karman vortex and measures the fluid velocity in a pipe based on the detection signals of these ultrasonic sensors, a drive signal is generated to drive each transmitter of the ultrasonic sensor. a phase comparator that detects the cycle of Karman vortex generation based on the phase difference between the output transmitter and the detection signal output from the receiver of these ultrasonic sensors, and detects the fluid velocity from this cycle; A signal switching circuit is provided between the sensor and the phase comparator to selectively input the drive signal that drives the transmitter and the detection signal output from the receiver into the phase comparator, and the signal switching circuit that controls the output abnormality of each receiver. A sensor abnormality monitoring circuit is provided between the transmitter and each of the ultrasonic sensors to turn on/off the supply of the drive signal. and a switch that is turned OFF, and further, the signal switching circuit inputs the detection signal output from the receiver of the ultrasonic sensor into a phase comparator when the abnormality detection signal is not output from the sensor abnormality monitoring circuit, When an abnormality detection signal is output from the sensor abnormality monitoring circuit, the phase comparator stops receiving the detection signal from the receiver in which the abnormality has occurred, and transmits the detection signal to the receiver of the normal ultrasonic sensor. The detection signal from
Further, the switch is configured to control the sensor abnormality monitoring circuit from the sensor abnormality monitoring circuit.
It is characterized in that when an abnormality detection signal is output that detects an abnormality in the output of the receiver of the ultrasonic sensor, the supply of the drive signal on the side of the ultrasonic sensor where the abnormality has occurred is turned off.

[0008]

According to the invention of claim 1, when the sensor abnormality monitoring circuit does not output an abnormality detection signal, the signal switching circuit allows the detection signals output from both receivers of the ultrasonic sensor to be sent to the phase comparator. This allows the fluid velocity to be normally detected from the phase difference between these detection signals. In addition, when an abnormality detection signal is output from the sensor abnormality monitoring circuit, the signal switching circuit stops receiving the detection signal from the receiver of the ultrasonic sensor in which the abnormality has occurred.
Since the drive signal that drives the transmitter of the normally functioning ultrasonic sensor can be output to the phase comparator, the drive signal and the normally functioning ultrasonic sensor's transmitter can be output to the phase comparator. It is possible to detect the cycle of Karman vortex generation from the phase difference with the detection signal taken from the receiver, and to detect the fluid velocity from this cycle. That is,
Even if an abnormality such as a drop in output occurs in the receiver of one of the two ultrasonic sensors, the signal switching circuit allows the Karman vortex to be detected using the other ultrasonic sensor. This allows the flow rate measurement to be continued without being interrupted.

According to the invention of claim 2, the output abnormalities of the receivers of the two sets of ultrasonic sensors are monitored, and when the receiver of one ultrasonic sensor causes an output abnormality, the transmitter of the transmitter is monitored. Since an abnormality is notified by lighting the light emitter, the operator can quickly perform tasks such as replacing the ultrasonic sensor by looking at the light emitter.

According to the third aspect of the invention, when an abnormality detection signal is output from the sensor abnormality monitoring circuit, the signal switching circuit stops receiving the detection signal from the receiver of the ultrasonic sensor in which the abnormality has occurred. However, since the drive signal that drives the transmitter of the normally functioning ultrasonic sensor is output to the phase comparator, the drive signal and the normally functioning ultrasonic sensor are output to the phase comparator. It is possible to detect the cycle of Karman vortex generation from the phase difference with the detection signal taken from the sensor receiver, and to detect the fluid velocity from this cycle. That is, among the two sets of ultrasonic sensors,
Even if an abnormality such as a decrease in output occurs in the receiver of one ultrasonic sensor, the signal switching circuit allows Karman vortex detection to be performed using the other ultrasonic sensor,
This allows the flow rate measurement to be continued without being interrupted. In addition, when the receiver of one ultrasonic sensor causes an output abnormality, a switch is installed between the transmitter and the transmitter of each ultrasonic sensor based on the abnormality detection signal from the sensor abnormality monitoring circuit. OF
Since the switching is made to F, it is possible to stop supplying the drive signal to the transmitter of the ultrasonic sensor in which the abnormality has occurred.

[0011]

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a circuit configuration diagram of a vortex flowmeter, and the reference numeral 1 shown in this figure is a conduit through which fluid flows, and the central part of this conduit 1 is used to generate a Karman vortex in the fluid. A vortex generating column 2 is provided. Further, two sets of ultrasonic sensors 3 and 4 are provided downstream of the vortex generating column 2. The ultrasonic sensor 3 includes an ultrasonic transmitter 5 that emits ultrasonic waves, and converts the received ultrasonic vibrations into electrical signals.
That is, the ultrasonic sensor 4 is composed of an ultrasonic receiver 6 that outputs as a detection signal, and the ultrasonic sensor 4 includes:
Like the ultrasonic sensor 3, it is composed of an ultrasonic transmitter 7 that emits ultrasonic waves, and an ultrasonic receiver 8 that outputs the received ultrasonic vibrations as an electrical detection signal,
Ultrasonic transmitters 5,
The ultrasonic wave outputted from 7 is propagated, and the ultrasonic wave propagated through the fluid is further received by ultrasonic receivers 6 and 8.

Next, a circuit for driving the ultrasonic transmitters 5 and 7 of the ultrasonic sensors 3 and 4 and for processing detection signals output from the ultrasonic transmitters 6 and 8 will be explained. The reference numeral 9 in the figure is a transmitter that outputs a drive signal for transmitting ultrasonic waves from the ultrasonic transmitters 5 and 7, and the reference numerals 10 and 11 are transmitters that output driving signals for transmitting ultrasonic waves from the ultrasonic receivers 6 and 8. This is an amplification circuit that amplifies the output detection signal. The detection signals amplified in the amplifier circuits 10 and 11 are as follows:
sensor abnormality monitoring circuits 12, 13, signal switching circuit 14,
15 and 15, respectively. Also,
The same drive signal is used to drive the ultrasonic transmitters 5 and 7 from the transmitter 9 in order to prevent a phase shift. The sensor abnormality monitoring circuit 12,1
3, the capacitors 12A and 13A temporarily hold the peak of the periodically changing detection signal, and the difference between the voltage value indicating this peak and a preset reference voltage value is calculated. Comparators 12B and 13B that output the difference as an abnormality monitoring signal, and light emitting diodes 12C and 1 that turn on when the voltage value of the abnormality monitoring signal is equal to or higher than a certain value.
3C, and the abnormality monitoring signal is finally supplied to signal switching circuits 14 and 15.

The signal switching circuits 14 and 15 include an amplifier 6
The route (1) where the detection signal is supplied from the oscillator 9 and the route (2) where the drive signal is supplied from the oscillator 9 are selectively connected to the route (3) leading to the phase comparator 16. The switching of 1) and (2) is performed when the sensor abnormality monitoring circuits 12 and 13 output an abnormality monitoring signal (abnormality detection signal) of a certain voltage value or higher. That is, the signal switching circuits 14 and 15 normally
) and (3) are connected, but when an abnormality monitoring signal of a certain voltage value or higher is output from the sensor abnormality monitoring circuits 12 and 13, the connection between routes (2) and (3) is interrupted. It is something that can be switched.

In the present embodiment, routes (1) and (3) of both signal switching circuits 14 and 15 are connected under normal conditions;
, 15, routes (2) and (3) are not connected. That is, in this embodiment, both the receivers 6 and 8 of the ultrasonic sensors 3 and 4 do not become abnormal, but only one of the receivers 6, 8 becomes abnormal.
It is assumed that it is 8.

The phase comparator 16 compares the phases of the two input detection signals and outputs a sinusoidal alternating signal according to the amount of phase difference between these detection signals. The signal corresponds to the fluid velocity. That is, in this vortex flowmeter, Karman vortices are generated alternately on both sides of the vortex generation column 2, and from the phase difference of the detection signal that changes according to the Karman vortices that are generated alternately,
The period of Karman vortex generation is detected and the fluid velocity is measured from this period. In addition, one signal switching circuit 14
Or when 15 is connected to routes (2) and (3) (in this case, the other signal switching circuit 14 or 15 is connected to routes (1) and (3))
, a phase difference between a drive signal that drives the transmitters 5 and 7 of one ultrasonic sensor 3 or 4 and a detection signal taken in from the receivers 6 and 8 of the ultrasonic sensors 3 and 4 driven by the drive signal. From this, the cycle of Karman vortex generation is detected. Further, the signal indicating the fluid velocity outputted from the phase comparator 16 is outputted to an output circuit 17, and in this output circuit 17, based on the signal outputted from the phase comparator 16, , outputs a signal proportional to the flow rate of the fluid flowing in the pipe 1.

In FIG. 1, reference numerals 18 and 19 indicate switches provided between the transmitter 9 and each of the ultrasonic sensors 3 and 4, respectively. These switches 18 are for turning on/off the output of the drive signal to each transmitter 5, 7, and the ON/OFF switching is performed when an abnormality monitoring signal of a certain voltage value or more is sent from the sensor abnormality monitoring circuits 12, 13. That is, this is performed on the condition that an abnormality detection signal is output from the sensor abnormality monitoring circuits 12 and 13.

The signal flow of the vortex flowmeter constructed as above will be explained in order of stroke. Note that the following description assumes that an abnormality in which the output decreases has occurred in the receiver 6 of the ultrasonic sensor 3.

[1] The detection signal of the receiver 6 is sent to the amplifier 1
0 to the sensor abnormality monitoring circuit 12, and in this sensor abnormality monitoring circuit 12, the difference between the voltage value indicating the peak of the periodically changing detection signal and the preset reference voltage value. is taken, and this difference is output as an abnormality monitoring signal. As a result, when the output of the detection signal of the receiver 6 of the ultrasonic sensor 5 decreases, the voltage value of the abnormality monitoring signal tends to increase as the degree of decrease in the output of the detection signal increases.

[2] If an abnormality occurs in the receiver 6 of the ultrasonic sensor 3 and the voltage value of the abnormality monitoring signal exceeds a certain value (abnormality detection signal),
The light emitting diode 12C lights up, and the signal switching circuit 14 also operates. That is, in the signal switching circuit 14, the route connected to (1) and (3) is (2).
) (3), whereby a drive signal for driving the transmitter 7 of the ultrasonic sensor 4 is supplied to the phase comparator 16. Note that the transmitter 5
, 7 are the same drive signal outputted from the oscillator 9 in order to prevent a phase shift, so the same drive signal may be used to drive the oscillator 5.

[3] In the phase comparator 16,
A drive signal for driving the transmitter 7 of the ultrasonic sensor 4 taken in via routes (2) and (3) of the signal switching circuit 14 and via routes (1) and (3) of the signal switching circuit 15. The cycle of Karman vortex generation is detected from the phase difference between the received detection signal from the receiver 7 of the ultrasonic sensor 4, and the fluid velocity in the pipe 1 is measured from this cycle.

[4] As shown in [2] above, the switch 18 is set to OFF based on the output of the abnormality monitoring signal in which the voltage value exceeds a certain value, and the switch 18 is set to OFF for the ultrasonic sensor 3 in which the abnormality has occurred. The supply of the drive signal is cut off.

As explained above, in the vortex flowmeter shown in this embodiment, when the sensor abnormality monitoring circuit 12 outputs an abnormality monitoring signal (abnormality detection signal) with a voltage value equal to or higher than a certain value, the signal switching circuit 14, the reception of the detection signal from the receiver 6 of the ultrasonic sensor 3 in which an abnormality has occurred is stopped, and the drive signal for driving the transmitter 7 of the normally functioning ultrasonic sensor 4 is sent to the phase comparator 16. Furthermore, in this phase comparator 16, the cycle of Karman vortex generation is detected from the phase difference between the drive signal and the detection signal taken from the receiver 8 of the normally functioning ultrasonic sensor 4. ,
The fluid velocity was detected from this period. That is, even if an abnormality such as a decrease in output occurs in the receiver 6 of one of the two ultrasonic sensors 3 and 4, the other ultrasonic sensor 4 can detect the Karman vortex. This allows the flow rate measurement to be carried out continuously without being interrupted, thereby providing the effect of improving work efficiency.

[0023] In this embodiment, the explanation has been made on the assumption that the receiver 6 of the ultrasonic sensor 3 has an abnormality in which the output decreases. If this occurs, the routes of the signal switching circuit 15 from routes (1) and (3) are switched to routes (2) and (3) in accordance with the output of the error monitoring signal from the sensor error monitoring circuit 13. As a result, the reception of the detection signal from the receiver 8 of the ultrasonic sensor 4 in which the abnormality has occurred is stopped, and the drive signal for driving the transmitter 5 of the normally functioning ultrasonic sensor 3 is sent to the phase comparator 16. Furthermore, in this phase comparator 16, the cycle of Karman vortex generation is detected from the phase difference between the drive signal and the detection signal taken from the receiver 6 of the normally functioning ultrasonic sensor 3. The fluid velocity is detected from this period.

[0024]

As is clear from the above description, according to the invention of claim 1, when an abnormality detection signal is output from the sensor abnormality monitoring circuit, the signal switching circuit automatically detects an abnormality in the ultrasonic sensor in which an abnormality has occurred. stops taking in the detection signal from the receiver of the ultrasonic sensor, outputs a drive signal that drives the transmitter of the normally functioning ultrasonic sensor to the phase comparator, and then outputs a drive signal that drives the transmitter of the normally functioning ultrasonic sensor to the phase comparator. The cycle of Karman vortex generation is detected from the phase difference with the detection signal taken from the receiver of a normally functioning ultrasonic sensor, and the fluid velocity is detected from this cycle. In other words, even if an abnormality such as a decrease in output occurs in the receiver of one of the two ultrasonic sensors, the other ultrasonic sensor can detect the Karman vortex, and this Flow rate measurement can be continued without interruption.

According to the invention of claim 2, when the receiver of one of the ultrasonic sensors causes an output abnormality, the abnormality of the ultrasonic sensor is notified by lighting the light emitting device. By allowing the operator to see the device, it is possible to quickly carry out tasks such as replacing the ultrasonic sensor.

According to the third aspect of the invention, the supply of the drive signal between the transmitter and the transmitter of each ultrasonic sensor is turned ON/OFF.
Since a switch is provided for each of the ultrasonic sensors to turn off, and when an abnormality occurs in the receiver of the ultrasonic sensor, the switch is turned off. Therefore, it is possible to supply a drive signal to the transmitter of the ultrasonic sensor in which the abnormality has occurred. This provides the effect of preventing the transmitter of the ultrasonic sensor from operating in vain.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a vortex flowmeter.

[Explanation of symbols]

1 Pipeline 2 Vortex generation column 3 Ultrasonic sensor 4 Ultrasonic sensor 5 Transmitter 6 Receiver 7 Transmitter 8 Receiver 9 Transmitter 12 Sensor abnormality monitoring circuit 12C Light emitting diode (light emitter) 13 Sensor abnormality monitoring circuit 13C Light emitting diode (light emitter) 14 Signal switching circuit 15 Signal switching circuit 16 Phase comparator 18 Switch 19 Switch

Claims (3)

[Claims] 1. A vortex generating column is provided in a conduit, and two sets of ultrasonic sensors each consisting of a transmitter and a receiver are used to detect the Karman vortices generated in the vortex generating column, and these ultrasonic sensors The vortex flowmeter is configured to measure the fluid velocity in a pipe based on the detection signal of the ultrasonic sensor, and includes a transmitter that outputs a drive signal for driving each transmitter of the ultrasonic sensor; a phase comparator that detects a cycle of Karman vortex generation based on a detection signal output from a receiver and detects fluid velocity from this cycle; and a phase comparator that is provided between the ultrasonic sensor and the phase comparator, and A signal switching circuit that selectively inputs the drive signal that drives the transmitter of the ultrasonic sensor and the detection signal output from the receiver into a phase comparator, and a signal switching circuit that monitors the receiver's output abnormality and detects it when an output abnormality occurs. and a sensor abnormality monitoring circuit that outputs an abnormality detection signal, and the signal switching circuit controls the detection output from the receiver of the ultrasonic sensor when the abnormality detection signal is not output from the sensor abnormality monitoring circuit. When a signal is captured into a phase comparator and an abnormality detection signal is output from the sensor abnormality monitoring circuit, the phase comparator stops receiving the detection signal from the receiver in which the abnormality has occurred, and A vortex flowmeter characterized in that a drive signal for driving an transmitter of a sound wave sensor is input into the phase comparator. 2. A vortex generating column is provided in a conduit, and two sets of ultrasonic sensors each consisting of a transmitter and a receiver are used to detect the occurrence of Karman vortices generated in the vortex generating column. In a vortex flowmeter that measures the fluid velocity in a pipe based on the detection signals of sonic sensors, based on the phase difference of the detection signals output from the receivers of these ultrasonic sensors,
A phase comparator that detects the cycle of Karman vortex generation and detects the fluid velocity from this cycle, and a sensor that is installed between the ultrasonic sensor and the phase comparator and monitors output abnormalities of each receiver. an abnormality monitoring circuit, each of the sensor abnormality monitoring circuits having a light emitter,
A vortex flowmeter characterized in that the light emitter is turned on when an abnormal output of a receiver of the ultrasonic sensor is detected. 3. A vortex generating column is provided in a conduit, and two sets of ultrasonic sensors each consisting of a transmitter and a receiver are used to detect the occurrence of Karman vortices generated in the vortex generating column. In a vortex flowmeter that measures fluid velocity in a pipe based on a detection signal of a sonic sensor, a transmitter that outputs a drive signal for driving each transmitter of the ultrasonic sensor;
A phase comparator that detects the cycle of Karman vortex generation based on the phase difference between the detection signals output from the receivers of these ultrasonic sensors, and detects the fluid velocity from this cycle, and the ultrasonic sensor and the phase comparator. A signal switching circuit is provided between each of them to selectively input the drive signal that drives the transmitter and the detection signal output from the receiver into the phase comparator, and the signal switching circuit that monitors the output abnormality of each receiver and outputs the signal. A sensor abnormality monitoring circuit that outputs an abnormality detection signal when an abnormality occurs, and a switch that is provided between the transmitter and each of the ultrasonic sensors and turns on/off the supply of the drive signal. The signal switching circuit, when no abnormality detection signal is output from the sensor abnormality monitoring circuit,
When a detection signal output from a receiver of the ultrasonic sensor is captured in a phase comparator, and an abnormality detection signal is output from the sensor abnormality monitoring circuit, a receiver in which an abnormality has occurred is transmitted to the phase comparator. The switch stops capturing the detection signal from the ultrasonic sensor, and captures the detection signal from the receiver of the normal ultrasonic sensor and the drive signal for driving the transmitter of the ultrasonic sensor into the phase comparator, and the switch: A vortex flow meter characterized in that, when an abnormality detection signal is output from the sensor abnormality monitoring circuit, supply of a drive signal to the ultrasonic sensor in which the abnormality has occurred is turned off.