JP4379173B2 - Fluid flow measuring device - Google Patents

Description

  The present invention relates to a flow measuring device having at least a pair of ultrasonic transmitters / receivers and measuring a flow velocity and / or a flow rate of a fluid based on an ultrasonic propagation time between the ultrasonic transmitters / receivers.

  FIG. 3 shows a conventional ultrasonic flow measuring device, in which an opening / closing means 52 and a measuring unit 53 are arranged in order from the upstream side in a fluid flow path 51 through which a fluid such as gas flows. The opening / closing means 51 includes a valve body portion 55 that opens and closes the valve seat 54 of the fluid flow path 51 and a drive portion 56 such as a stepping motor that drives the valve body portion 55.

  The measuring unit 53 is configured by arranging at least a pair of ultrasonic transmitters and receivers 57 and 58 on the upstream side and the downstream side of the fluid flow path 51, and the ultrasonic wave transmitted from one ultrasonic transmitter 57 is the fluid. The flow is obliquely crossed in the forward direction and received by the other ultrasonic transceiver 58, and then ultrasonic waves are transmitted from the other ultrasonic transceiver 58. At this time, the ultrasonic waves from the ultrasonic transmitter / receiver 58 reach the ultrasonic transmitter / receiver 57 by crossing the fluid flow diagonally in the opposite direction.

  The measurement unit of the controller 59 measures the flow velocity of the fluid flowing through the fluid flow path 51 based on the above-described difference in ultrasonic propagation time, and multiplies it by the cross-sectional area of the fluid flow path 51 and the correction coefficient as necessary. The flow rate is calculated.

  When an abnormality occurs in the flow velocity and / or flow rate flowing through the fluid flow channel 51, the monitoring unit of the controller 59 outputs a signal to the opening / closing means 52, and the driving unit 56 closes the valve body unit 55. Of course, it is also conceivable to perform alarm notification together.

The opening / closing means 52 receives the output of the earthquake monitoring unit when the seismic device incorporated in the controller 59 detects an earthquake with a predetermined seismic intensity or more, and when the pressure of the fluid flow path 51 becomes abnormal. In response to the signal from the pressure sensor 60, the closing operation is performed (see, for example, Patent Document 1).
JP-A-8-94464

  However, in the conventional measuring device, when foreign matter such as dust adheres to the valve body of the opening / closing means, the corresponding valve seat cannot be closed, and the fluid continues to partially flow. There was a thing.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to make it possible to monitor the operating state of the opening / closing means by rationally arranging ultrasonic transceivers.

  In order to solve the above-described conventional problems, a fluid flow measurement device according to the present invention opens and closes at least a pair of ultrasonic transmitters / receivers disposed upstream and downstream of a fluid passage, Opening / closing means in which the one ultrasonic transmitter / receiver is disposed in a unit, a calculation unit for calculating a flow rate and / or a flow rate of a fluid flowing in a fluid path based on an ultrasonic propagation time between the ultrasonic transmitters / receivers, And a monitoring unit that monitors the operating state of the valve body of the opening / closing means based on the ultrasonic propagation time between the ultrasonic transmitters / receivers. It was also used for body position detection.

  According to the fluid flow measuring device of the present invention, by arranging one ultrasonic transmitter / receiver in the valve body part of the opening / closing means, the flow rate and / or flow rate of the fluid can be measured and the valve body part of the opening / closing means is closed. It is also possible to detect whether or not the device is in a safe state and to obtain a highly reliable safe operation.

  In the embodiment of the present invention, at least a pair of ultrasonic transmitters / receivers disposed on the upstream side and downstream side of the fluid passage, the fluid passage is opened and closed, and the one ultrasonic transmitter / receiver is disposed in the valve body portion. The ultrasonic propagation time between the ultrasonic transmission / reception unit, the calculation unit for calculating the flow velocity and / or flow rate of the fluid flowing in the fluid passage based on the ultrasonic propagation time between the ultrasonic transceivers and the ultrasonic transceiver And a monitoring unit for monitoring the operating state of the valve body of the opening / closing means, and the ultrasonic transmitter / receiver can be used not only for flow measurement but also for checking the operation of the opening / closing means.

  And the ultrasonic propagation time in the state which the valve body closed outside the area | region of the ultrasonic propagation time in a flow measurement state was set.

  Further, when the ultrasonic propagation time in the state where the valve body is closed is deviated from a set value, it is assumed that the valve body is not fully closed, and a warning notification is performed, or A separate second safety valve was forcibly closed.

  Propagating the vibration generated by the ultrasonic transceiver to the valve body of the switchgear is useful for removing attached dust and the like.

  Hereinafter, the embodiment will be described with reference to the drawings.

Example 1
In FIG. 1, an opening / closing means 2 is disposed in a fluid flow path 1 through which a fluid such as a gas flows, and a pressure detector 3 is provided upstream thereof. The opening / closing means 2 includes a drive unit 3 such as a stepping motor and a valve body unit 5 that opens and closes a valve seat 4 formed in the fluid flow path 1 in association with the drive unit 3.

  At least a pair of ultrasonic transmitters / receivers 6 and 7 set so that the ultrasonic waves obliquely cross the fluid flowing through the fluid flow path 1 are provided. One ultrasonic transmitter / receiver 6 is disposed on the fluid flow path 1 side, and the other ultrasonic transmitter / receiver 7 is disposed on the valve body portion 5 of the opening / closing means 2, which are opposed to the valve seat 4 therebetween. It is.

  In normal times, the ultrasonic waves transmitted from one ultrasonic transmitter 6 cross the fluid flow obliquely in the forward direction and are received by the other ultrasonic transmitter / receiver 7, and then from the other ultrasonic transmitter / receiver 7. Ultrasound is transmitted. At this time, the ultrasonic wave from the ultrasonic transmitter / receiver 7 crosses the flow of the fluid diagonally in the opposite direction and reaches one ultrasonic transmitter / receiver 6.

  The calculation unit of the controller 8 measures the flow velocity of the fluid flowing through the fluid flow path 1 based on the above-described difference in ultrasonic propagation time, and multiplies it by the cross-sectional area of the fluid flow path 1 and the correction coefficient as necessary. The flow rate is calculated. When an abnormality occurs in the flow velocity and / or flow rate flowing through the fluid flow path 1, the controller 8 outputs a signal to the opening / closing means 2, and the drive unit 3 closes the valve body unit 5. Of course, it is also conceivable to perform alarm notification together.

  Further, even when the valve body 5 of the opening / closing means 2 is in contact with the valve seat 4, ultrasonic transmission / reception is performed between the ultrasonic transmitters / receivers 6, 7 even in a so-called closed state. In this case, since the interval between the ultrasonic transmitters / receivers 6 and 7 is small, the propagation time difference of ultrasonic waves is smaller than that during normal flow measurement, and the monitoring unit of the controller 8 is closed based on this small time difference. The state is to be detected.

  As shown in FIG. 2, the valve body portion 5 has a cap shape, and an elastic material 9 such as rubber is attached to the flange portion corresponding to the valve seat 4, and the ultrasonic wave is attached to the central concave portion. A transceiver 7 is incorporated. That is, the ultrasonic transmitter / receiver 7 includes a piezoelectric vibrator 10 bonded to the inner surface of the concave wall of the valve body 5 and an acoustic matching layer 11 bonded to the outer surface of the top wall. The inside of the recessed portion thus made is hermetically sealed from the fluid flowing through the fluid flow path 1.

  Moreover, since the ultrasonic transmitter / receiver 7 may co-operate with the valve body 5, the lead wires 12 and 13 are formed flexibly.

  In the above configuration, normally, the flow velocity and / or flow rate of the fluid flowing through the fluid flow path 1 is measured based on the difference in ultrasonic propagation time between the ultrasonic transceivers 6 and 7, and the measured value is abnormal. In this case, for example, when the flow velocity or flow rate is higher than the set value, the opening / closing means 2 is closed via the controller 8, and the subsequent fluid flow is stopped. Of course, even when the pressure of the fluid flow path 1 becomes an abnormal value, the controller 8 closes the opening / closing means 2 in response to the output of the pressure detector 3.

  In this embodiment, the state in which the valve body 5 of the opening / closing means 2 is closed is also monitored by the difference in ultrasonic propagation time between the ultrasonic transmitters / receivers 6 and 7. As described above, since the length of the ultrasonic propagation path is greatly different between the normal flow measurement and the closing monitoring of the valve body 5, the difference in ultrasonic propagation time is also greatly different, and the two forms are clearly distinguished. It can be done.

  If foreign matter such as dust adheres to the valve body part 5 and a gap is generated between the valve seat 4 and the difference between the ultrasonic propagation time set as a normally closed state, naturally, The controller 8 performs warning notification on the assumption that the valve body portion 5 is closed abnormally.

  If further safety is taken into consideration, it is conceivable to close the second safety valve separately provided together with the warning notification.

  In the above embodiment, the ultrasonic wave is directly propagated between at least a pair of ultrasonic transceivers. However, in addition, at least the ultrasonic wave transmitted from one ultrasonic transceiver is transmitted through the fluid flow path. A so-called reflection type that is reflected once and propagated to the other ultrasonic transmitter / receiver is also fully conceivable.

  As described above, in this embodiment, at least a pair of ultrasonic transmitters / receivers that perform flow measurement are also used for detecting an abnormality of the opening / closing means, and safety and the like can be improved with a simple configuration. .

  Furthermore, as another embodiment, a maintenance mode is set using the controller 8, the ultrasonic transmitters / receivers 6 and 7 are periodically operated to vibrate the valve body 5 of the opening / closing means 2, and the adhered foreign matter. It is also conceivable to remove. The vibration in this case may be in a mode different from that during flow measurement.

  Even if an ultrasonic wave is transmitted from the ultrasonic wave transmitter / receiver 6 not directly related to the opening / closing means 2, the other ultrasonic wave transmitter / receiver 7 that receives the ultrasonic wave generates vibrations. Accordingly, it is also conceivable to operate only the ultrasonic transmitter / receiver 7 related to the opening / closing means 2.

  As described above, according to the present invention, at least a pair of ultrasonic transmitters / receivers that measure fluid flow are also used for detecting abnormality of the opening / closing means, and in particular, measurement safety of gaseous fluid such as flammable gas. Suitable for use.

Schematic cross-sectional view of a fluid flow measuring device showing an embodiment of the present invention Enlarged sectional view of the opening / closing means Schematic sectional view of a conventional fluid flow measurement device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluid flow path 2 Opening-closing means 3 Drive part 4 Valve seat 5 Valve body part

Claims (4)

At least a pair of ultrasonic transmitters / receivers arranged on the upstream side and downstream side of the fluid passage, opening / closing means for opening / closing the fluid passage and arranging the one ultrasonic transmitter / receiver in the valve body, and the ultrasonic transmission / reception A calculation unit for calculating the flow velocity and / or flow rate of the fluid flowing in the fluid passage based on the ultrasonic propagation time between the devices, and the valve body of the opening / closing means based on the ultrasonic propagation time between the ultrasonic transceivers. A fluid flow measuring device comprising a monitoring unit for monitoring an operating state. The fluid flow measuring device according to claim 1, wherein the ultrasonic wave propagation time in a state where the valve body is closed is set outside the ultrasonic wave propagation time region in the flow measurement state. The fluid according to claim 2, wherein when the ultrasonic wave propagation time in a state where the valve body is closed is deviated from a set value, it is assumed that the valve body is not fully closed, and a warning is notified. Flow measuring device. When the ultrasonic wave propagation time with the valve body closed is deviated from the set value, it is assumed that the valve body is not fully closed, and the separately provided second safety valve is forcibly closed. The fluid flow measuring device according to claim 2 or 3.

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