JP2015075405A - Flow rate control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate control device which is capable of accurately obtaining a flow rate of a fluid even when a zero value is shifted in a period from zero value correction until the restart of the flow rate control device.SOLUTION: A flow rate control device 10 includes: a flow channel 20 in which a fluid flows; a flowmeter sensor unit 30 which measures a flow rate of the fluid flowing in the flow channel; an adjustment valve 40 which adjusts the flow rate of the fluid flowing in the flow channel, to a set flow rate; and a control unit 50 which calculates a flow rate of the fluid on the basis of a signal outputted from the flowmeter sensor unit. The control unit performs zero value monitoring in which it is monitored that a calculated flow rate value is a zero value till the flow channel is opened by the adjustment value after zero value correction in which the flow rate value calculated when the flow channel is closed by the adjustment valve is to be zero. The control unit performs the zero value correction if the calculated flow rate value exceeds a range of a preliminarily set threshold during the zero value monitoring.

Description

  The present invention relates to a flow control device.

  In fluid transportation in various industries such as a semiconductor manufacturing field, a chemical factory, a food field, and a bio field, a flow control device that controls an operation of bringing the actual flow rate of a fluid closer to a preset flow rate value is widely used. The flow rate control device includes a flow meter sensor unit that measures the flow rate of the fluid that flows through the flow path, and an adjustment valve that adjusts the flow rate of the fluid that flows through the flow path to a set flow rate. Sensors used in the flowmeter sensor unit may be affected by changes in environmental temperature or aging, and the measured flow rate value may not show zero even though no fluid is flowing in the flow path. . In order to accurately measure the flow rate, the flow rate control device performs zero value correction (see Patent Document 1). First, the value measured by the flow meter sensor when the flow path is closed by the regulating valve is stored as a basic value (a value when the flow rate is zero, that is, a zero value). Then, the flow rate is obtained by correcting the stored basic value by increasing or decreasing the value measured by the flowmeter by opening the flow path with the adjusting valve.

JP 2008-82799 A

  In the technique described in Patent Document 1, when the flow rate control device is restarted immediately after the zero value correction, that is, when the flow rate is controlled by the adjusting valve, a problem that the zero value is shifted occurs. Absent.

  However, the zero value is not monitored after the zero value correction is performed until the flow control device is restarted. For this reason, there exists a possibility that a zero value may shift | deviate before restarting a flow control apparatus. Causes of the zero value shift include environmental and fluid temperature changes, deterioration of various sensors and circuits, and the like.

  If the zero value deviates before the flow control device is restarted, an accurate flow rate can no longer be obtained even if the flow control device is restarted. The flow control device is required to be able to operate immediately (control the flow rate) when a flow control command is issued from the outside. In a manufacturing apparatus having a severe manufacturing tact, for example, a semiconductor manufacturing apparatus, there is no time for performing zero value correction after the flow control command is issued.

  Although it is conceivable to check the deviation of the zero value that has occurred between the zero value correction and the re-operation of the flow control device from the malfunction status of the product, the countermeasure against the deviation of the zero value becomes extremely slow. For this reason, it is necessary to quickly notice the deviation of the zero value that occurs between the zero value correction and the restart of the flow control device.

  Therefore, the present invention provides a flow rate control device that can accurately obtain the flow rate of a fluid even when the zero value is deviated between when the zero value correction is performed and when the flow rate control device is restarted. The purpose is to provide.

  The flow rate control device of the present invention that achieves the above object includes a flow path in which a fluid flows, a flowmeter sensor unit that measures the flow rate of the fluid flowing in the flow path, and a flow rate in which the flow rate of the fluid flowing in the flow path is set. And a control unit that calculates the flow rate of the fluid based on the signal output from the flowmeter sensor unit. The control unit performs zero value correction in which the flow rate value calculated when the flow path is closed by the adjustment valve is zero, and then calculates the flow rate until the flow path is opened by the adjustment valve. Perform zero value monitoring to monitor that the value is zero. And the said control part performs the said zero value correction | amendment, when the calculated flow value exceeds the range of the preset threshold value during the said zero value monitoring.

  Since the controller corrects the zero value when the calculated flow rate value exceeds the preset threshold range during the zero value monitoring, there is no possibility that the zero value is shifted before the flow control device is restarted. Therefore, when the flow control is performed again by the flow control device, the flow rate of the fluid can be obtained quickly and accurately, and as a result, the flow control can be performed quickly and accurately.

It is a schematic structure figure showing a flow control device concerning an embodiment. It is a flowchart which shows the procedure of zero value monitoring. It is a flowchart which shows the procedure which further detects that abnormality occurred based on the peak voltage difference during zero value monitoring. It is a flowchart which shows the procedure which further detects that abnormality had arisen based on the amplification magnification during zero value monitoring. It is a flowchart which shows the procedure which further detects that abnormality has arisen based on the deviation | shift amount with respect to the initial value of the output value of a flowmeter sensor part during zero value monitoring. It is a figure which shows typically a mode that the deviation | shift amount becomes large with respect to the initial value of the output value of a flowmeter sensor part, while performing zero value correction | amendment repeatedly during zero value monitoring.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. The dimensional ratios in the drawings are exaggerated for convenience of explanation, and are different from the actual ratios.

  Drawing 1 is a schematic structure figure showing flow control device 10 concerning an embodiment.

  With reference to FIG. 1, the flow rate control device 10 is generally described as follows. The flow path 20 through which the fluid flows, the flow meter sensor unit 30 that measures the flow rate of the fluid that flows through the flow path 20, and the flow rate of the fluid that flows through the flow path 20 It has the adjustment valve 40 which adjusts a flow rate to the set flow rate, and the control part 50 which calculates the flow volume of the fluid based on the signal output from the flowmeter sensor part 30. The flow path 20, the flow meter sensor unit 30, the adjustment valve 40, and the control unit 50 are housed in the casing 60 and unitize the flow control device 10. The flow control device 10 further includes a notification unit 70 that notifies the operation state of the device. The control unit 50 is connected to the flow meter sensor unit 30, the adjustment valve 40, and the notification unit 70. Further, the control unit 50 is connected to a device-side control unit 80 in an external manufacturing apparatus such as a semiconductor manufacturing apparatus. The control unit 50 transmits / receives a signal related to the flow rate of the fluid to and from the apparatus side control unit 80. And the control part 50 calculates the flow volume of the fluid, controls the action | operation of the adjustment valve 40, and adjusts the flow volume of the fluid which flows through the flow path 20 to the set flow volume. Hereinafter, the flow control device 10 of this embodiment will be described in detail.

  The casing 60 includes a fluid inflow pipe 21 that communicates with the flow path 20 and a fluid outflow pipe 22. In the casing 60, the flow meter sensor unit 30 and the adjustment valve 40 are fixed by bolts, nuts, and the like. The fluid inflow pipe 21, the flowmeter sensor unit 30, the adjustment valve 40, and the fluid outflow pipe 22 are continuously connected in this order in the fluid flow direction. The casing 60 is formed from a resin material such as PVDF. By unitizing the flow control device 10, the flow control device 10 can be reduced in size, and repair and replacement work can be easily performed.

  As long as the flow meter sensor unit 30 can measure the flow rate, the measurement method is not particularly limited. In the present embodiment, for example, a sensor unit for an ultrasonic flowmeter is applied. The ultrasonic flowmeter propagates ultrasonic vibrations in the fluid, and measures the flow velocity and flow rate of the fluid from the difference between the ultrasonic propagation time from the upstream side of the flow and the ultrasonic propagation time from the downstream side. The flowmeter sensor unit 30 includes a straight tube-shaped measurement tube 31 communicating with the fluid inflow tube 21 and two ultrasonic transmitters / receivers 32u and 32d attached to the outer peripheral surface of the measurement tube 31 so as to be separated from each other in the axial direction. ing. Each of the ultrasonic transmitters / receivers 32u and 32d includes a cylindrical transmission body 33 fixed to the outer peripheral surface of the measurement tube 31 so as to surround the measurement tube 31, and a disk shape fixed to the end surface in the axial direction of the transmission body 33. Ultrasonic transducers 34u and 34d. The transmission body 33 has a substantially conical shape in which the outer diameter decreases from the axial end face to which the ultrasonic transducers 34u and 34d are fixed toward the other axial end face. The ultrasonic transducers 34u and 34d are applied with a voltage between axial end faces, and generate ultrasonic vibrations by expanding and contracting in the axial direction. The ultrasonic transducers 34 u and 34 d are arranged with a gap between them and the outer peripheral surface of the measurement tube 31. The ultrasonic vibration generated by the ultrasonic transducers 34 u and 34 d propagates only to the transmission body 33.

  In the flow meter sensor unit 30, the ultrasonic vibration transmitted from one ultrasonic transmitter / receiver 32u is received by the other ultrasonic transmitter / receiver 32d via the fluid in the measurement tube 31, and the two ultrasonic transmitter / receivers 32u and 32d are received. Measure the ultrasonic propagation time between. Next, the ultrasonic transmitters / receivers 32u and 32d on the transmitting side and the receiving side are switched, and the ultrasonic vibration transmitted from the other ultrasonic transmitter / receiver 32d is received by one ultrasonic transmitter / receiver 32u through the fluid in the measurement tube 31. Then, the ultrasonic propagation time between the two ultrasonic transceivers 32u and 32d is measured. The flow velocity and flow rate of the fluid are measured from the difference between these ultrasonic propagation times.

  The flowmeter sensor unit 30 for the ultrasonic flowmeter is not limited to the type using the illustrated straight pipe-shaped measurement tube 31. A type that uses a U-shaped measurement tube, a type that propagates ultrasonic vibration generated from an ultrasonic transceiver obliquely to the fluid flow direction in the measurement tube, and reflects ultrasonic vibration on the inner surface of the measurement tube There are types that propagate, and any type of flow meter sensor unit can be applied.

  The adjustment method of the adjustment valve 40 is not particularly limited as long as the flow rate can be adjusted. In the present embodiment, for example, a diaphragm valve that adjusts the flow rate of the fluid by adjusting the opening of the valve body in accordance with the supplied operation pressure is applied. The control unit 50 adjusts the operation pressure supplied to the adjustment valve 40 based on the signal related to the flow rate of the fluid received from the device-side control unit 80. The operation pressure is adjusted using an electrically driven solenoid valve (not shown).

  The control unit 50 is mainly composed of a CPU and has a storage unit such as a RAM or a ROM. A control program for controlling the entire flow control device 10 is stored in the ROM, and is read and executed by the CPU. The control unit 50 includes a flow meter amplifier unit 51. The flow meter amplifier unit 51 calculates the flow rate from the signal output from the flow meter sensor unit 30. The flow meter amplifier unit 51 includes a transmission circuit that outputs ultrasonic vibration of a fixed period to the ultrasonic transmitter / receiver 32u (or 32d) on the transmission side, and an ultrasonic vibration from the ultrasonic transmitter / receiver 32d (or 32u) on the reception side. , A comparison circuit that compares the propagation times of the ultrasonic vibrations, and an arithmetic circuit that calculates the flow rate from the propagation time difference output from the comparison circuit. The control unit 50 has a control circuit that feedback-controls the flow rate output from the flow meter amplifier unit 51 so as to be a set flow rate, and controls increase / decrease of the operation pressure supplied to the regulating valve 40. .

  The notification unit 70 includes a lamp, a speaker, and the like that issue an alarm. When it is determined that an abnormality has occurred in the flow control device 10, the control unit 50 operates the notification unit 70 to notify the operator of the abnormal state of the device.

  Next, the operation of this embodiment will be described.

  FIG. 2 is a flowchart showing the procedure of zero value monitoring. In the present embodiment, the control unit 50 also monitors other monitoring items as shown in FIGS. 3 to 5 until the flow rate control is restarted after the zero value correction. FIG. 3 is a flowchart showing a procedure for further detecting that an abnormality has occurred based on the peak voltage difference during zero value monitoring. FIG. 4 shows that an abnormality has occurred based on the amplification factor during zero value monitoring. FIG. 5 is a flowchart showing a procedure for further detecting that an abnormality has occurred based on the amount of deviation of the output value of the flow meter sensor unit 30 from the initial value during zero value monitoring. is there.

  First, after incorporating the flow control device 10 into a piping system such as a semiconductor manufacturing device, the flow control device 10 is initialized. Initial setting is performed through each step of measurement preparation and flow rate zero setting. The flow path 20 is opened by the regulating valve 40, a fluid is caused to flow through the flow path 20, bubbles in the fluid are extracted, and the flow path 20 is filled with the fluid (measurement preparation). The flow path 20 is closed by the regulating valve 40, and the flow rate and flow rate of the fluid are measured from the difference between the ultrasonic propagation time from the upstream side of the flow and the ultrasonic propagation time from the downstream side by the flow meter sensor unit 30 (flow rate) Measurement). Then, the measured flow rate is set to the initial flow rate zero (flow rate zero setting). Thereby, the preparation for starting the flow control is completed.

  In the present embodiment, after starting the flow rate control, the control unit 50 performs zero value correction so that the flow rate value calculated when the flow path 20 is closed by the regulating valve 40 is zero. Thereafter, until the flow path 20 is opened by the regulating valve 40, zero value monitoring is performed to monitor that the calculated flow rate value is zero. And the control part 50 is performing zero value correction | amendment, when the calculated flow rate value remove | deviates from the preset threshold value during zero value monitoring. Hereinafter, the procedure of zero value monitoring will be described with reference to FIG.

  The device-side control unit 80 issues a flow control command to the control unit 50 of the flow control device 10. In response to the flow control command, the control unit 50 feedback-controls the opening degree of the regulating valve 40, and starts flow-rate feedback control so that the set flow rate is obtained (step S1).

  The device-side control unit 80 issues a flow control stop command to the control unit 50 of the flow control device 10 (step S2).

  In response to the flow control stop command, the control unit 50 fully closes the adjustment valve 40 and closes the flow path 20. With the flow path 20 closed by the regulating valve 40, the flow meter amplifier unit 51 of the control unit 50 calculates the flow rate from the signal output from the flow meter sensor unit 30 (step S3).

  When the regulating valve 40 is fully closed, the calculated flow rate value should theoretically become a flow rate “zero”, but in reality, it often does not become a flow rate “zero”. The causes include, for example, a difference in the characteristics of the ultrasonic transducers 34u and 34d, aged deterioration of the joined state with the transmission body 33, and the like. Therefore, it is confirmed whether or not the calculated flow rate value is an abnormal flow rate value. The controller 50 determines whether or not the flow rate value calculated in step S3 is within a preset threshold value (1) (step S4). The threshold value (1) is set to a flow rate value that cannot be considered in the fully closed state. The range of the threshold (1) can be set as appropriate. For example, the threshold (1) is set within a range of ± 2% of the designed maximum flow rate.

  If the calculated flow rate value exceeds the range of the threshold value (1), it is suspected that the flow rate control device 10 has water leakage or equipment damage. When the calculated flow rate value exceeds the range of the threshold value (1) (step S4: “NO”), the control unit 50 determines that an abnormality has occurred in the flow control device 10 and activates the notification unit 70. The operator is notified of the abnormal state of the device (step S5). Thereafter, the control unit 50 ends the process.

  When the calculated flow rate value is within the range of the threshold value (1) (step S4: “YES”), it is confirmed whether or not the flow rate requires zero value correction. The controller 50 determines whether or not the flow rate value calculated in step S3 is outside the preset threshold value (2) (step S6). In the threshold value (2), a flow rate value within an error range of the flow rate “zero” is set. The range of the threshold value (2) can be set as appropriate. For example, the threshold value (2) is set to a range of ± 1% of the designed maximum flow rate.

  When the calculated flow rate value is within the range of the threshold value (2) (step S6: “NO”), it is not necessary to perform zero value correction, and the process proceeds to zero value monitoring in step S8.

  When the calculated flow rate value is within the range of the threshold value (1) but exceeds the range of the threshold value (2) (step S6: “YES”), the control unit 50 determines to perform zero value correction. To do. The control unit 50 performs zero value correction that newly sets the calculated flow rate value to zero (step S7).

  The control unit 50 starts monitoring whether or not the zero value is stable until the next flow rate control command is received from the apparatus-side control unit 80, that is, until the flow path 20 is opened by the regulating valve 40 (step). S8).

  Zero value monitoring is to monitor that the calculated flow rate value is a zero value, and the same processing as steps S4 to S7 is performed (steps S9 to S12). The zero value monitoring is performed based on an average flow value of a plurality of flow values calculated during a preset time, or a flow value calculated every preset time.

  The controller 50 determines whether or not the calculated flow rate value is within the range of the threshold value (1) (step S9).

  When the calculated flow rate value exceeds the range of the threshold value (1) (step S9: “NO”), the control unit 50 determines that an abnormality has occurred in the flow rate control device 10 and activates the notification unit 70. The operator is notified of the abnormal state of the device (step S10). Thereafter, the control unit 50 ends the process.

  When the calculated flow value is within the range of the threshold value (1) (step S9: “YES”), the control unit 50 determines whether or not the calculated flow value is outside the range of the threshold value (2). (Step S11). When the calculated flow rate value is within the range of the threshold value (2) (step S11: “NO”), it is not necessary to perform zero value correction. The process returns to step S9, and the control unit 50 continues to monitor the zero value until the flow path 20 is opened by the regulating valve 40.

  When the calculated flow rate value is within the range of the threshold value (1) but exceeds the range of the threshold value (2) (step S11: “YES”), the control unit 50 determines to perform zero value correction. To do. The control unit 50 performs zero value correction that newly sets the calculated flow value to zero (step S12). The process returns to step S9, and the control unit 50 continues to monitor the zero value until the flow path 20 is opened by the regulating valve 40.

  When the control unit 50 receives the next flow control command from the device-side control unit 80 during the zero value monitoring, the control unit 50 immediately terminates the zero value monitoring, feedback-controls the opening degree of the regulating valve 40, and sets the set flow rate. The flow shifts to feedback control of the flow rate.

  The zero value is monitored after the zero value correction is performed until the flow control device 10 is restarted. When the zero value is shifted, the shift can be quickly noticed, and the zero value is corrected as necessary. ing. For this reason, there is no possibility that the zero value is shifted before the flow control device 10 is restarted. Therefore, when the flow control is performed again by the flow control device 10, the flow rate of the fluid can be obtained quickly and accurately, and as a result, the flow control can be performed quickly and accurately.

  Next, a procedure for further detecting that an abnormality has occurred based on the peak voltage difference during the zero value monitoring will be described with reference to FIG.

  The flowmeter sensor unit 30 of the present embodiment includes two ultrasonic transducers 34u and 34d as first and second sensors that detect a physical quantity of fluid as a voltage value signal at two different points. The ultrasonic propagation time in the fluid is measured as a physical quantity by the two ultrasonic transducers 34u and 34d.

  When the zero value monitoring is started, the control unit 50 transmits ultrasonic waves from the upstream ultrasonic transducer 34u serving as the first sensor to the downstream ultrasonic transducer 34d serving as the second sensor. Similarly, ultrasonic waves are transmitted from the downstream ultrasonic transducer 34d to the upstream ultrasonic transducer 34u (step S11).

  The control unit 50 determines the maximum amplitude voltage value (peak voltage) Y (R) of the received wave detected by the upstream ultrasonic transducer 34u and the maximum amplitude voltage of the received wave detected by the downstream ultrasonic transducer 34d. The peak voltage difference Z (R) from the value (peak voltage) X (R) is measured (step S12).

  The control unit 50 stores an initial value Z (0) of a peak voltage difference measured when the flow control device 10 is in operation. The controller 50 compares the measured value Z (R) of the peak voltage difference with the initial value Z (0) of the peak voltage difference (step S13).

  The control unit 50 calculates a threshold value (Z (R) −Z (0)) obtained by subtracting the initial value Z (0) of the peak voltage difference from the measured value Z (R) of the peak voltage difference. It is determined whether it is within the range of 3) (step S14).

Z (0): Voltage difference of maximum amplitude at initial value (peak voltage difference)
= X (0) -Y (0)
Z (R): Maximum amplitude voltage difference (peak voltage difference) in the current measured value
= X (R) -Y (R)
here,
X (0): Voltage value (peak voltage) of the maximum amplitude at the initial value (transmitting ultrasonic waves from the ultrasonic transducer 34u on the upstream side to the ultrasonic transducer 34d on the downstream side)
Y (0): Maximum amplitude voltage value (peak voltage) at the initial value (ultrasonic waves are transmitted from the ultrasonic transducer 34d on the downstream side to the ultrasonic transducer 34u on the upstream side)
X (R): Voltage value (peak voltage) of the maximum amplitude in the current measured value (transmitting ultrasonic waves from the ultrasonic transducer 34u on the upstream side to the ultrasonic transducer 34d on the downstream side)
Y (R): Voltage value (peak voltage) of the maximum amplitude in the current actual measurement value (ultrasonic waves are transmitted from the ultrasonic transducer 34d on the downstream side to the ultrasonic transducer 34u on the upstream side)
It is.

  The range of the threshold value (3) can be set as appropriate. For example, the threshold value (3) is a range of 5% of the maximum voltage value that can be measured by the flowmeter amplifier unit 51.

  The ultrasonic flowmeter has a characteristic that “the peak voltage difference is constant”. Therefore, when the “peak voltage difference is not constant”, the zero value is not shifted, but some disturbance, for example, an increase in individual difference between the ultrasonic transducers 34u and 34d (deterioration of one ultrasonic transducer, etc.) occurs. Suggests that it occurred. From the rule of thumb, it is known that when the phenomenon “the peak voltage difference is not constant” appears, the calculated value of the flow rate deviates from the actual flow rate. When the calculated value (Z (R) −Z (0)) exceeds the threshold value (3) (step S14: “NO”), the control unit 50 determines that an abnormality has occurred in the flow control device 10. Then, the notification unit 70 is operated to notify the operator of the abnormal state of the apparatus (step S15). Thereafter, the control unit 50 ends the process.

  When the calculated value is within the range of the threshold value (3) (step S14: “YES”), the zero value monitoring process similar to steps S9 to S12 is performed (steps S16 to S19).

  The controller 50 determines whether or not the calculated flow rate value is within the range of the threshold value (1) (step S16).

  When the calculated flow rate value exceeds the range of the threshold value (1) (step S16: “NO”), the control unit 50 determines that an abnormality has occurred in the flow control device 10 and activates the notification unit 70. The operator is notified of the abnormal state of the device (step S17). Thereafter, the control unit 50 ends the process.

  When the calculated flow rate value is within the range of the threshold value (1) (step S16: “YES”), the control unit 50 determines whether or not the calculated flow rate value is outside the range of the threshold value (2). (Step S18). When the calculated flow rate value is within the range of the threshold value (2) (step S18: “NO”), it is not necessary to perform zero value correction. The process returns to step S12, and the control unit 50 continues to monitor the zero value until the flow path 20 is opened by the regulating valve 40, and measures the peak voltage difference.

  When the calculated flow rate value is within the range of the threshold value (1) but exceeds the range of the threshold value (2) (step S18: “YES”), the control unit 50 determines to perform zero value correction. To do. The control unit 50 performs zero value correction with the calculated flow rate value as a new flow rate zero (step S19). The process returns to step S12, and the control unit 50 continues to monitor the zero value until the flow path 20 is opened by the regulating valve 40, and measures the peak voltage difference.

  When the control unit 50 receives the next flow control command from the device-side control unit 80 during the zero value monitoring, the control unit 50 immediately terminates the zero value monitoring, feedback-controls the opening degree of the regulating valve 40, and sets the set flow rate. The flow shifts to feedback control of the flow rate.

  The controller 50 determines that an abnormality has occurred when the difference between the measured value of the peak voltage difference and the initial value of the peak voltage difference deviates from the preset threshold (3) during the zero value monitoring. For this reason, before the flow control device 10 is restarted, an abnormality of the apparatus, that is, an abnormality of the system can be sensed at an early stage, and quick repair or replacement is possible. Since an increase in individual differences between the ultrasonic transducers 34u and 34d causes an abnormality, it is possible to detect defects caused by individual differences without adjusting individual differences between the ultrasonic transducers 34u and 34d. It is possible to take necessary measures.

  Next, a procedure for further detecting that an abnormality has occurred based on the amplification magnification during zero value monitoring will be described with reference to FIG.

  The control unit 50 of the present embodiment is configured to be able to change at least one amplification magnification (gain value) of a signal output from the flow meter sensor unit 30 or a signal input to the flow meter sensor unit 30.

  When starting the zero value monitoring, the control unit 50 transmits ultrasonic waves from one side, for example, the upstream ultrasonic transducer 34u to the other side, for example, the downstream ultrasonic transducer 34d. The ultrasonic waves transmitted from one ultrasonic transducer 34u are amplified at an appropriate magnification so as to have a constant voltage value before being received by the other ultrasonic transducer 34d (step S21).

  The controller 50 measures the amplification magnification when the ultrasonic wave is amplified (step S22).

  The control unit 50 determines whether or not the amplification magnification for amplifying the ultrasonic wave is within a preset threshold value (4) (step S23). The range of the threshold value (4) can be set as appropriate. For example, the threshold value (4) is a range that is 90% or more of the maximum value of the magnification that can be detected by the flowmeter amplifier unit 51 and that bubbles can be detected.

  When the amplification magnification exceeds the range of the threshold value (4), it is suggested that some disturbance, for example, bubbles are mixed when a liquid is flowing through the flow path 20. Note that the amplification factor also increases when a droplet is mixed while the gas is flowing. When the amplification factor exceeds the threshold (4) range (step S23: “NO”), the control unit 50 determines that an abnormality has occurred in the flow control device 10, operates the notification unit 70, and operates the device. Is notified to the worker (step S24). Thereafter, the control unit 50 ends the process.

  When the amplification factor is within the range of the threshold value (4) (step S23: “YES”), the zero value monitoring process similar to steps S9 to S12 is performed (steps S25 to S28).

  The controller 50 determines whether or not the calculated flow rate value is within the range of the threshold value (1) (step S25).

  When the calculated flow rate value exceeds the range of the threshold value (1) (step S25: “NO”), the control unit 50 determines that an abnormality has occurred in the flow control device 10 and activates the notification unit 70. The operator is notified of the abnormal state of the device (step S26). Thereafter, the control unit 50 ends the process.

  When the calculated flow value is within the range of the threshold value (1) (step S25: “YES”), the control unit 50 determines whether or not the calculated flow value is outside the range of the threshold value (2). (Step S27). When the calculated flow rate value is within the range of the threshold value (2) (step S27: “NO”), it is not necessary to perform zero value correction. The process returns to step S22, and the control unit 50 continues to monitor the zero value until the flow path 20 is opened by the regulating valve 40, and measures the amplification factor.

  When the calculated flow rate value is within the range of the threshold value (1) but exceeds the range of the threshold value (2) (step S27: “YES”), the control unit 50 determines to perform zero value correction. To do. The control unit 50 performs zero value correction that newly sets the calculated flow rate value to zero (step S28). The process returns to step S22, and the control unit 50 continues to monitor the zero value until the flow path 20 is opened by the regulating valve 40, and measures the amplification factor.

  When the control unit 50 receives the next flow control command from the device-side control unit 80 during the zero value monitoring, the control unit 50 immediately terminates the zero value monitoring, feedback-controls the opening degree of the regulating valve 40, and sets the set flow rate. The flow shifts to feedback control of the flow rate.

  The controller 50 determines that an abnormality has occurred when the amplification factor deviates from the preset threshold value (4) during the zero value monitoring. For this reason, before the flow control device 10 is restarted, a system abnormality can be detected at an early stage, and quick repair and replacement are possible. Since bubbles are mixed in the flow path 20 and cause an abnormality, it is possible to detect the malfunction and take necessary measures such as deaeration.

  Next, a procedure for further detecting that an abnormality has occurred based on the amount of deviation from the initial value of the output value of the flow meter sensor unit 30 during zero value monitoring will be described with reference to FIG.

  When starting the zero value monitoring (step S31), the controller 50 performs the same processing as steps S9 to S12 (steps S32 to S35).

  When the calculated flow rate value exceeds the range of the threshold value (1) (step S32: “NO”), the control unit 50 determines that an abnormality has occurred in the flow control device 10, and activates the notification unit 70. The operator is notified of the abnormal state of the device (step S33). Thereafter, the control unit 50 ends the process.

  When the calculated flow value is within the range of the threshold value (1) (step S32: “YES”), the control unit 50 determines whether or not the calculated flow value is outside the range of the threshold value (2). (Step S34). When the calculated flow rate value is within the range of the threshold value (2) (step S34: “NO”), it is not necessary to perform zero value correction. The process proceeds to step S37.

  When the calculated flow rate value is within the range of the threshold value (1) but exceeds the range of the threshold value (2) (step S34: “YES”), the control unit 50 determines to perform zero value correction. To do. The control unit 50 performs zero value correction for setting the calculated flow rate value to a new flow rate zero (step S35).

  The controller 50 stores, as an initial value, a value output from the flow meter sensor unit 30 when the first zero value correction is performed during operation of the apparatus. The control unit 50 compares the current value output from the flowmeter sensor unit 30 when the zero value correction is performed in step S35 with the initial value stored during operation of the apparatus (step S36).

  The control unit 50 determines whether or not the calculated value obtained by subtracting the initial value from the current value of the output value of the flowmeter sensor unit 30 is within a preset threshold value (5) (step S37). The range of the threshold value (5) can be set as appropriate. For example, it is a range of ± 3% of the maximum flow rate.

  If the current value of the flow meter sensor unit 30 when the zero value is corrected is greatly deviated from the initial value, not only the accurate flow rate cannot be calculated, but also some abnormality, for example, a failure has occurred in the flow meter sensor unit 30. Or it may be more appropriate to recognize that the lifetime has come to an end. When the calculated value exceeds the range of the threshold value (5) (step S37: “NO”), the control unit 50 determines that an abnormality has occurred in the flow control device 10, operates the notification unit 70, and operates the device. Is notified to the operator (step S38). Thereafter, the control unit 50 ends the process.

  When the calculated value is within the range of the threshold value (5) (step S37: “YES”), the flowmeter sensor unit 30 is normal, and there is no need to end the process. The process returns to step S <b> 32, and the control unit 50 continues to monitor the zero value until the flow path 20 is opened by the adjustment valve 40.

  When the control unit 50 receives the next flow control command from the device-side control unit 80 during the zero value monitoring, the control unit 50 immediately terminates the zero value monitoring, feedback-controls the opening degree of the regulating valve 40, and sets the set flow rate. The flow shifts to feedback control of the flow rate.

  The control unit 50 determines that an abnormality has occurred when the calculated value obtained by subtracting the initial value from the current value of the output value of the flow meter sensor unit 30 deviates from the preset threshold value (5) during the zero value monitoring. . For this reason, before the flow control device 10 is restarted, a system abnormality can be detected at an early stage, and quick repair and replacement are possible. Since a failure has occurred in the flow meter sensor unit 30 while the zero value correction is being performed repeatedly, an abnormality may occur, so that the malfunction is detected and necessary measures such as replacement of the flow meter sensor unit 30 are taken. It becomes possible to do.

  FIG. 6 is a diagram schematically illustrating how the output value of the flow meter sensor unit 30 increases with respect to the initial value while the zero value correction is repeatedly performed during the zero value monitoring. is there. In FIG. 6, the solid line indicates the change in the output value V (R) of the flow meter sensor unit 30, and the symbol Δa indicates the threshold (2) range that is the error range of the flow rate “zero”. V (0) indicates an initial value output from the flow meter sensor unit 30 when zero value correction is performed during operation of the apparatus. Symbol Δb indicates the range of the threshold value (5) described above.

  During the zero value monitoring, the output value of the flow meter sensor unit 30 may deviate from the initial value, and the calculated flow value may deviate. When the calculated flow rate value exceeds the range of the threshold value (2) (time t1, t2, step S34 in FIG. 5: “YES”), zero value correction is performed (step S35 in FIG. 5).

  After the zero value correction is repeated a plurality of times, the output value of the flow meter sensor unit 30 shifts again at time t3, and the calculated flow rate value shifts. Before the calculated flow rate value exceeds the range of the threshold value (2), the calculated value obtained by subtracting the initial value from the current value of the output value of the flow meter sensor unit 30 exceeds the range of the threshold value (5) (time t4). At this time t4, the abnormal state of the apparatus is notified (step S37 in FIG. 5: “NO”, step S38).

  As described above, in the present embodiment, the control unit 50 performs the adjustment after performing zero value correction in which the flow rate value calculated when the flow path 20 is closed by the adjustment valve 40 is zero. Until the flow path 20 is opened by the valve 40, zero value monitoring is performed to monitor that the calculated flow rate value is zero. And the control part 50 is performing zero value correction | amendment, when the calculated flow value exceeds the range of the preset threshold value during zero value monitoring. For this reason, there is no possibility that the zero value is shifted before the flow control device 10 is restarted. Therefore, when the flow control is performed again by the flow control device 10, the flow rate of the fluid can be obtained quickly and accurately, and as a result, the flow control can be performed quickly and accurately.

  During the zero value monitoring, the control unit 50 measures the peak voltage difference between the two ultrasonic transducers 34u and 34d as the first and second sensors, and the measured value of the peak voltage difference and the peak voltage measured when the apparatus is in operation. When the difference between the difference and the initial value exceeds a preset threshold (3), it is determined that an abnormality has occurred. For this reason, before the flow control device 10 is restarted, a system abnormality can be detected at an early stage, and quick repair and replacement are possible. Since an increase in individual difference between the two sensors (ultrasonic transducers 34u and 34d) causes an abnormality, the individual difference between the sensors (ultrasonic transducers 34u and 34d) does not need to be adjusted. It is possible to detect a malfunction caused by the difference and take necessary measures.

  The control unit 50 determines that an abnormality has occurred when the amplification factor exceeds the preset threshold (4) during the zero value monitoring. For this reason, before the flow control device 10 is restarted, a system abnormality can be detected at an early stage, and quick repair and replacement are possible. Since bubbles are mixed in the flow path 20 and cause an abnormality, it is possible to detect the malfunction and take necessary measures such as deaeration.

  During the zero value monitoring, the control unit 50 outputs the value output from the flow meter sensor unit 30 when the zero value correction is performed and the output from the flow meter sensor unit 30 when the zero value correction is performed during operation of the apparatus. It is determined that an abnormality has occurred when the difference from the initial value exceeds a preset threshold (5) range. For this reason, before the flow control device 10 is restarted, a system abnormality can be detected at an early stage, and quick repair and replacement are possible. Since a failure has occurred in the flow meter sensor unit 30 while the zero value correction is being performed repeatedly, an abnormality may occur, so that the malfunction is detected and necessary measures such as replacement of the flow meter sensor unit 30 are taken. It becomes possible to do.

  The flow control device 10 further includes a notification unit 70 that notifies the operating state of the device, and the control unit 50 operates the notification unit 70 to notify the abnormal state of the device when it is determined that an abnormality has occurred. By notifying the system abnormality by the notification unit 70 in this way, it is possible to realize quick repair or replacement.

  The flow path 20, the flowmeter sensor unit 30, the adjustment valve 40, and the control unit 50 are housed in a casing 60 having a fluid inflow pipe 21 and a fluid outflow pipe 22 communicating with the flow path 20. By unitizing in this way, the flow control device 10 can be reduced in size, and repair and replacement work can be easily performed.

  In addition, this invention is not limited to embodiment mentioned above, It can change suitably. For example, although the example in which the flowmeter sensor unit 30 and the regulating valve 40 are arranged in this order along the flow direction of the fluid is illustrated, the order may be reversed.

  The flow meter sensor unit 30 is not limited to an ultrasonic flow meter. For example, it is possible to apply a flow meter sensor unit for a differential pressure type flow meter that detects a pressure that is a physical quantity of a fluid at two different points as a voltage value signal and measures a flow rate based on a differential pressure between the two points. . In addition, for example, a vortex flowmeter sensor unit for a vortex flowmeter that measures the flow rate passing through the flow path by providing a vortex generator and a vortex detection means in the flow path through which the fluid flows can be applied.

10 Flow control device,
20 channels,
21 fluid inflow pipe,
22 Fluid outflow pipe,
30 Flow meter sensor section,
31 measuring tube,
32u upstream ultrasonic transceiver,
32d downstream ultrasonic transceiver,
33 Transmitter,
34u upstream ultrasonic transducer (first sensor),
34d downstream ultrasonic transducer (second sensor),
40 Regulating valve,
50 control unit,
51 Flow meter amplifier section,
60 casing,
70 Notification section,
80 Device-side control unit.

Claims (6)

A flow path through which fluid flows;
A flowmeter sensor unit for measuring the flow rate of the fluid flowing through the flow path;
An adjustment valve for adjusting the flow rate of the fluid flowing through the flow path to a set flow rate;
A controller that calculates the flow rate of the fluid based on the signal output from the flowmeter sensor unit,
The control unit performs zero value correction in which the flow rate value calculated when the flow path is closed by the adjustment valve is zero, and then calculates the flow rate until the flow path is opened by the adjustment valve. A flow rate control device that performs zero value monitoring for monitoring that a value is a zero value, and performs the zero value correction when the calculated flow rate value exceeds a preset threshold range during the zero value monitoring. The flow meter sensor unit includes first and second sensors that detect a physical quantity of a fluid as a voltage value signal at two different points,
The control unit measures a peak voltage difference between the peak voltage detected by the first sensor and the peak voltage detected by the second sensor during the zero value monitoring, and a measured value of the peak voltage difference The flow control device according to claim 1, wherein it is determined that an abnormality has occurred when a difference from an initial value of a peak voltage difference measured during operation of the device exceeds a preset threshold range. The control unit is capable of changing an amplification factor of at least one of a signal output from the flow meter sensor unit or a signal input to the flow meter sensor unit,
The flow control device according to claim 1, wherein the control unit determines that an abnormality has occurred when the amplification magnification exceeds a preset threshold range during the zero value monitoring.   During the zero value monitoring, the control unit outputs a value that is output from the flow meter sensor unit when the zero value correction is performed, and from the flow meter sensor unit when the zero value correction is performed during operation of the apparatus. The flow rate control device according to claim 1, wherein it is determined that an abnormality has occurred when a difference from the output initial value exceeds a preset threshold range. It further has a notification unit that notifies the operating state of the device,
The flow control device according to any one of claims 2 to 4, wherein when the control unit determines that an abnormality has occurred, the notification unit is operated to notify an abnormal state of the device.   The unit comprising the flow path, the flowmeter sensor unit, the adjustment valve, and the control unit housed in a casing having a fluid inflow pipe and a fluid outflow pipe communicating with the flow path. The flow control device according to any one of?