Flow rate adjusting device, flow rate adjusting system, and method for controlling flow rate adjusting device

Abstract

To prevent overshooting and control delays from occurring with respect to a flow rate setting value when switching from standby mode to flow rate adjustment mode. [Solution] A flow control device is provided which comprises an ultrasonic flow measurement unit (10) that measures the flow rate of the liquid, a flow rate adjustment unit (20) that adjusts the flow rate of the liquid flowing out of the measurement flow path by moving the valve body unit toward or away from the valve hole, a flow rate setting unit (32) that sets the liquid flow rate set value, and a control unit (31) that controls the flow rate adjustment unit (20) in either a flow rate adjustment mode or a standby mode, wherein, when executing the flow rate adjustment mode, the control unit (31) controls the flow rate adjustment unit (20) to move the valve body unit to a target position that changes depending on the flow rate difference between the flow rate measurement value and the flow rate set value so that the liquid flow rate measurement value becomes the flow rate set value, and when executing the standby mode, the control unit (31) controls the flow rate adjustment unit (20) to move the valve body unit to a standby position where the valve body unit does not contact the valve hole and then maintain the standby position.

Description

[Technical Field]

[0001] The present invention relates to a flow control device, a flow control system, and a control method for a flow control device. [Background technology]

[0002] Conventionally, a flow control device is known that includes a flow measurement unit that measures the flow rate of a liquid, and adjusts the flow rate of the liquid passing through the valve orifice by moving a valve body unit toward or away from the valve orifice so that the flow rate measured by the flow measurement unit becomes a preset set flow rate (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-138200 A Summary of the Invention [Problem to be solved by the invention]

[0004] The flow control device disclosed in Patent Document 1, for example, receives liquid discharged from a pump installed upstream via a pipe, adjusts the flow rate of the supplied liquid, and discharges it into the pipe installed downstream. The liquid discharged from the flow control device flows out from an outlet end installed at the downstream end of the pipe. The flow control device is incorporated as part of a flow control system that includes a pump that sucks in and discharges liquid from an inlet end, and pipes upstream and downstream of the flow control device.

[0005] When the flow control system stops the transport of liquid from the inlet end to the outlet end, for example, the pump is stopped, and the on-off valves located in the piping upstream of the flow control device are closed, and the on-off valves located in the piping downstream of the flow control device are closed. The flow control device, for example, maintains the position of the valve body at the time the flow control system is stopped. In this case, because the on-off valves located upstream and downstream of the flow control device are closed, the flow control system remains in a state of stopping the transport of liquid from the inlet end to the outlet end even if the position of the valve body is maintained.

[0006] However, for example, if the position of the valve body is inappropriate and the opening is excessively large when the flow control system is stopped, there is a possibility that the flow rate of the liquid will be excessively large compared to the target flow rate when the flow control system resumes transporting the liquid from the inlet end to the outlet end, resulting in an overshoot.Furthermore, for example, if the position of the valve body is inappropriate and the opening is too small (for example, fully closed) when the flow control system is stopped, there is a possibility that a control delay will occur, which will lengthen the time it takes for the flow rate of the liquid to reach the target flow rate when the flow control system resumes transporting the liquid from the inlet end to the outlet end.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a flow control device, a flow control system, and a control method for a flow control device that can prevent overshooting of the flow rate set value and control delays when switching from standby mode to flow rate adjustment mode. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following means. The flow control device of the present invention comprises a flow measurement unit that measures the flow rate of liquid flowing through a measurement flow path; a flow adjustment unit that adjusts the flow rate of liquid flowing out of the measurement flow path by moving a valve body along an axis in a direction toward or away from a valve hole; a flow setting unit that sets a flow rate set value of the liquid adjusted by the flow adjustment unit; and a control unit that controls the flow adjustment unit in either a flow adjustment mode or a standby mode, wherein when executing the flow adjustment mode, the control unit controls the flow adjustment unit to move the valve body to a target position that changes depending on the flow rate difference between the flow rate measurement value and the flow rate set value so that the flow rate measurement value of the liquid measured by the flow measurement unit becomes the flow rate set value, and when executing the standby mode, the control unit controls the flow adjustment unit to move the valve body to a standby position where the valve body does not contact the valve hole and then maintain the standby position.

[0009] According to the flow control device of the present invention, when switching from the flow control mode to the standby mode, the control unit controls the flow control unit to move the valve element to a standby position where the valve element does not contact the valve orifice and then maintain the standby position. Because the standby position is a position where the valve element does not contact the valve orifice, the valve element has a larger opening than the fully closed position where the valve element contacts the valve orifice. This improves the ability to follow the flow rate setting compared to when switching from the fully closed position to the flow control mode, preventing control delays. Furthermore, even if the valve element is excessively separated from the valve orifice and has an excessively large opening when switching from the flow control mode to the standby mode, the valve element moves to the standby position and maintains the standby position. This prevents overshooting due to an excessively large opening of the valve element when switching from the standby mode to the flow control mode.

[0010] In the flow control device of the present invention, the target position may be set between a lower limit position corresponding to the lower limit of the flow rate setting value that can be set by the flow rate setting unit and an upper limit position corresponding to the upper limit of the flow rate setting value that can be set by the flow rate setting unit, and the standby position may be a position that is farther away from the valve hole than the lower limit position.

[0011] With the flow control device of this configuration, the standby position is farther away from the valve hole than the lower limit position, so that the flow rate setting value is more responsive than when switching to flow control mode from the lower limit position, and control delays can be prevented.

[0012] The flow rate control device according to the present invention may be configured to include a standby position setting unit that sets the standby position at a predetermined position between the lower limit position and the upper limit position.

[0013] According to the flow control device of this configuration, by using the standby position setting unit to set the standby position to a predetermined position between the lower limit position and the upper limit position, it is possible to appropriately prevent overshoot and control delay from occurring when switching from standby mode to flow control mode.

[0014] In the flow control device of the present invention, the control unit may be configured to switch the standby mode to the flow control mode in response to receiving a first switching signal from a higher-level device that switches the standby mode to the flow control mode, and to switch the flow control mode to the standby mode in response to receiving a second switching signal from the higher-level device that switches the flow control mode to the standby mode.

[0015] According to the flow rate adjusting device having this configuration, it is possible to appropriately switch between the flow rate adjusting mode and the standby mode in response to the first switching signal and the second switching signal received from the higher-level device.

[0016] In the flow control device having the above configuration, the flow setting unit may set the flow rate setting value based on a flow rate setting signal for setting the flow rate setting value transmitted from the higher-level device, and the control unit may set the standby position based on a standby position setting signal for setting the standby position transmitted from the higher-level device.

[0017] According to the flow rate control device of this aspect, the flow rate setting value can be set based on the flow rate setting signal transmitted from the higher-level device, and the standby position can be set based on the standby position setting signal transmitted from the higher-level device.

[0018] A flow rate adjustment system according to the present invention is a flow rate adjustment system comprising a flow rate adjustment device and a host device that controls the flow rate adjustment device, wherein the flow rate adjustment device comprises: a flow rate measurement unit that measures the flow rate of liquid flowing through a measurement flow path; a flow rate adjustment unit that adjusts the flow rate of liquid flowing out of the measurement flow path by moving a valve body unit along an axis in a direction toward or away from a valve hole; a flow rate setting unit that sets a flow rate set value of the liquid adjusted by the flow rate adjustment unit; and a control unit that controls the flow rate adjustment unit in either a flow rate adjustment mode or a standby mode, wherein, when executing the flow rate adjustment mode, the control unit controls the flow rate adjustment unit to move the valve body unit to a target position that varies depending on the flow rate difference between the flow rate measurement value and the flow rate set value so that the flow rate measurement value of the liquid measured by the flow rate measurement unit becomes the flow rate set value, and when executing the standby mode, the control unit controls the flow rate adjustment unit to move the valve body unit to a target position that varies depending on the flow rate difference between the flow rate measurement value and the flow rate set value so that the flow rate measurement value of the liquid measured by the flow rate measurement unit becomes the flow rate set value and controls the flow control unit to maintain the standby position after moving the valve body portion to a standby position where the body portion does not contact the valve hole, and the higher-level device comprises: a mode transmission unit that transmits to the flow control device a first switching signal that switches the flow control device from the standby mode to the flow control mode and a second switching signal that switches the flow control device from the flow control mode to the standby mode, a flow transmission unit that transmits to the flow control device a flow setting signal for setting the flow rate set value, and a standby position transmission unit that transmits to the flow control device a standby position setting signal for setting the standby position, and the standby position transmission unit transmits the standby position setting signal to the flow control device so that the standby position in a predetermined standby mode varies depending on the flow rate set value in the flow control mode that is executed subsequent to the predetermined standby mode.

[0019] According to the flow control system of the present invention, when switching from the flow control mode to the standby mode, the control unit of the flow control device controls the flow control unit to move the valve disc to a standby position where the valve disc does not contact the valve orifice and then maintain the standby position. Because the standby position is a position where the valve disc does not contact the valve orifice, the opening degree is larger than in the fully closed position where the valve disc contacts the valve orifice. This improves the ability to follow the flow rate setting compared to when switching from the fully closed position to the flow control mode, preventing control delays. Furthermore, even if the valve disc is excessively separated from the valve orifice and the opening degree is excessive when switching from the flow control mode to the standby mode, the valve disc moves to the standby position and maintains the standby position. This prevents overshooting due to an excessive opening degree when switching from the standby mode to the flow control mode.

[0020] Furthermore, according to the flow control system of the present invention, the standby position transmitter of the higher-level device transmits a standby position setting signal to the flow control device so that the standby position in a predetermined standby mode varies according to the flow rate set value in a flow rate adjustment mode that is executed subsequent to the predetermined standby mode. When switching from the predetermined standby mode to the flow rate adjustment mode, the standby position becomes a position according to the flow rate set value in the flow rate adjustment mode, making it possible to appropriately prevent overshooting and control delays.

[0021] The flow control system according to the present invention may be configured to include a temperature detection unit that detects the temperature of the liquid flowing through the flow control device, and the standby position transmission unit may be configured to transmit the standby position setting signal to the flow control device so that the distance along the axis from the valve hole to the standby position becomes longer as the temperature of the liquid detected by the temperature detection unit increases.

[0022] With the flow control device of this configuration, the distance along the axis from the valve hole to the standby position increases as the temperature of the liquid detected by the temperature detection unit increases, thereby appropriately preventing malfunctions caused by the valve body unit and valve hole unit expanding and coming close to or into contact with each other as the temperature of the liquid increases.

[0023] The flow control system according to the present invention may include a pressure detection unit that detects the pressure of the liquid flowing into the flow control device, and the standby position transmission unit may be configured to transmit the standby position setting signal to the flow control device so that the distance along the axis from the valve hole to the standby position becomes shorter as the pressure of the liquid detected by the pressure detection unit increases.

[0024] With the flow control device of this configuration, the distance along the axis from the valve hole to the standby position becomes shorter as the pressure of the liquid detected by the pressure detection unit increases, thereby appropriately preventing the flow rate of the liquid from becoming excessive as the pressure of the liquid increases.

[0025] In the control method for flow rate adjustment according to the present invention, the flow rate adjustment device comprises a flow rate measuring unit that measures the flow rate of liquid flowing through a measurement flow path, a flow rate adjustment unit that adjusts the flow rate of liquid flowing out of the measurement flow path by moving a valve body along an axis in a direction toward or away from a valve hole, and a flow rate setting unit that sets a flow rate set value of the liquid adjusted by the flow rate adjustment unit, and comprises a flow rate adjustment process that controls the flow rate adjustment unit to move the valve body to a target position that varies depending on the flow rate difference between the flow rate measurement value and the flow rate set value so that the flow rate measurement value of the liquid measured by the flow rate measuring unit becomes the flow rate set value, and a standby process that moves the valve body to a standby position where the valve body does not contact the valve hole and then controls the flow rate adjustment unit to maintain the standby position.

[0026] According to the control method for a flow control device of the present invention, in the standby process, the flow control unit is controlled to move the valve element to a standby position where the valve element does not contact the valve orifice and then maintain the standby position. Because the standby position is a position where the valve element does not contact the valve orifice, the opening degree is larger than in the fully closed position where the valve element contacts the valve orifice. This improves the ability to follow the flow rate setting compared to when the flow control process is performed from the fully closed position, preventing control delays. Furthermore, even if the valve element is excessively separated from the valve orifice and the opening degree is excessive when switching from the flow control process to the standby process, the valve element moves to the standby position and remains in that standby position. This prevents overshooting due to an excessive opening degree when switching from the standby process to the flow control process. [Effects of the Invention]

[0027] According to the present invention, it is possible to provide a flow control device, a flow control system, and a control method for a flow control device that can prevent overshooting of the flow rate setting value and control delays when switching from standby mode to flow rate adjustment mode. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 2 is a partial vertical cross-sectional view showing an embodiment of a flow rate adjusting device. [Figure 2] 2 is a partial vertical cross-sectional view showing the ultrasonic flow rate measuring unit shown in FIG. 1. [Figure 3] 2 is a partial vertical cross-sectional view showing a flow rate adjusting section and an outlet-side channel section shown in FIG. 1. FIG. [Figure 4] 2 is a vertical cross-sectional view showing an inlet-side flow path section and a pressure sensor shown in FIG. 1. FIG. [Figure 5] FIG. 2 is a block diagram showing the configuration of a control device. [Figure 6] 1 is a schematic configuration diagram showing a flow control system in which a flow control device is installed. [Figure 7] FIG. 2 is a block diagram showing the configuration of a higher-level device. [Figure 8]10 is a flowchart showing an operation executed by a higher-level device. [Figure 9] 4 is a flowchart showing an operation performed by the flow rate control device. [Figure 10] 10 is a graph showing an example of a change in the opening degree of a valve body portion. [Figure 11] FIG. 1 is a schematic configuration diagram showing a flow rate adjusting system according to a first modified example of the present invention. [Figure 12] FIG. 10 is a schematic configuration diagram showing a flow rate adjusting system according to a second modified example of the present invention. [Figure 13] FIG. 10 is a schematic configuration diagram showing a flow rate adjusting system according to a third modified example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] A flow control device 100 according to one embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a partial vertical cross-sectional view showing one embodiment of the flow control device 100. Fig. 2 is a partial vertical cross-sectional view showing the ultrasonic flow measurement unit 10 shown in Fig. 1.

[0030] The flow control device 100 of this embodiment shown in Figure 1 comprises an ultrasonic flow measurement unit 10 that measures the flow rate of liquid that flows in from an inlet port 100a and flows through a straight-tube measurement flow path 14, a flow rate adjustment unit 20 that adjusts the flow rate of the liquid, a control device 30 that controls the flow rate adjustment unit 20, a housing unit 40 that accommodates the ultrasonic flow measurement unit 10, the flow rate adjustment unit 20, and the control device 30, an inlet-side flow path unit 50 that guides the fluid that flows in from the inlet port 100a to the upstream side of the measurement flow path 14, an outlet-side flow path unit 60 that guides the fluid that flows out from the downstream side of the measurement flow path 14 to the outlet port 100b, and a pressure sensor (pressure measurement unit) 70.

[0031] The liquid whose flow rate is adjusted by the flow rate control device 100 of this embodiment is, for example, a chemical liquid used in semiconductor manufacturing equipment, pure water, etc. The temperature of the liquid is, for example, in the room temperature range (e.g., 10°C or higher and lower than 50°C) or in the high temperature range (e.g., 50°C or higher and 80°C or lower).

[0032] The housing 40 of the flow control device 100 is fixed to an installation surface S with fastening bolts (not shown). The flow control device 100 is also connected to a host device 200 (see FIG. 5) via a cable 101, and receives power from an external device via the cable 101, and transmits and receives various signals to and from the host device 200.

[0033] The signal received from the higher-level device 200 is, for example, a flow rate setting signal indicating a set value of a target flow rate adjusted by the flow control device 100. Furthermore, the signal transmitted to the higher-level device 200 is, for example, a signal indicating the flow rate of the liquid calculated by the control device 30 based on the signal measured by the ultrasonic flow rate measurement unit 10, or a signal indicating the pressure of the liquid measured by the pressure sensor 70.

[0034] The ultrasonic flow rate measuring unit 10 measures the propagation time difference of ultrasonic waves emitted by a pair of transducers, an upstream transducer 11 arranged upstream of the measurement flow path 14 and a downstream transducer 12 arranged downstream of the measurement flow path 14, in order to obtain the flow rate of liquid flowing in from an inlet pipe (not shown) and circulating through a straight-tube measurement flow path 14.

[0035] 2, the ultrasonic flow measurement unit 10 has an upstream transducer 11 and a downstream transducer 12 arranged on an axis X2 parallel to an installation surface S, an inflow flow path 13 connected to an inflow flow path 50, a straight measurement flow path 14 connected to the inflow flow path 13 and extending along the axis X2 (second axis), and an outflow flow path 15 connected to an outflow flow path 60. The axis X2 is parallel to an axis X1 (first axis) which is the direction of advancement and retreat of a valve body 21 described later.

[0036] The upstream transducer 11 and the downstream transducer 12 are arranged at positions facing each other on the axis X2 with the measurement flow path 14 interposed therebetween, and are capable of transmitting and receiving ultrasonic signals. The ultrasonic signal transmitted by the upstream transducer 11 propagates through the fluid flowing through the measurement flow path 14 and is received by the downstream transducer 12.

[0037] Similarly, the ultrasonic signal emitted by the downstream transducer 12 propagates through the fluid flowing through the measurement flow path 14 and is received by the upstream transducer 11. Because the fluid flows from the upstream side to the downstream side through the measurement flow path 14, the propagation time of the ultrasonic signal emitted by the upstream transducer 11 to the downstream transducer 12 is shorter than the propagation time of the ultrasonic signal emitted by the downstream transducer 12 to the upstream transducer 11. The ultrasonic flow rate measurement unit 10 measures the flow rate of the fluid flowing through the measurement flow path 14 by utilizing this propagation time difference.

[0038] The transmission of ultrasonic signals by the upstream transducer 11 and the downstream transducer 12 is controlled by a control device 30 connected by signal lines 16 and 17 shown in Fig. 2. The reception of ultrasonic signals by the upstream transducer 11 and the downstream transducer 12 is transmitted to the control device 30 via signal lines 16 and 17. As will be described later, the control device 30 calculates a propagation time difference from the timing of transmission of ultrasonic signals instructed to the upstream transducer 11 and the downstream transducer 12 and the timing of reception of the corresponding ultrasonic signals received from the upstream transducer 11 and the downstream transducer 12, and calculates the flow rate of the fluid from the calculated propagation time difference.

[0039] The flow rate adjustment unit 20 adjusts the flow rate of the liquid flowing from the downstream side of the measurement flow path 14 to the outlet port 100b connected to the outlet piping (not shown) via the outlet-side flow path unit 60. As shown in Fig. 1, the flow rate adjustment unit 20 is arranged between the ultrasonic flow measurement unit 10 and the control device 30 in the direction of the axis Y, which is the installation direction perpendicular to the installation surface S. As shown in Fig. 1, in the direction of the axis Y, the ultrasonic flow measurement unit 10 is arranged at a position closest to the installation surface S, and the control device 30 is arranged at a position farthest from the installation surface S, with the flow rate adjustment unit 20 arranged between them.

[0040] Fig. 3 is a partial vertical cross-sectional view showing the flow rate adjustment unit 20 and the outlet-side channel section 60 shown in Fig. 1. As shown in Fig. 3, the flow rate adjustment unit 20 has a valve body section 21 that is inserted into a valve hole 62 formed in the outlet-side channel section 60, and an electric drive unit 22 that moves the valve body section 21 toward or away from the valve hole 62 along an axis X1 (first axis) that is parallel to the installation surface S. The flow rate adjustment unit 20 adjusts the flow rate of the liquid flowing out of the measurement channel 14 by moving the valve body section 21 toward or away from the valve hole 62 along the axis X1.

[0041] The electric driver 22 moves the valve body 21 back and forth along the axis X1 between a closed position indicated by a solid line in Fig. 3 and an open position indicated by a dashed line in Fig. 3. The flow rate adjuster 20 adjusts the amount of fluid flowing from the valve hole 62 into the valve chamber 63 by adjusting the position of the valve body 21 on the axis X1 using the electric driver 22.

[0042] Here, the configuration of the control device 30 will be described with reference to Fig. 5. Fig. 5 is a block diagram showing the configuration of the control device 30. As shown in Fig. 5, the control device 30 has a control unit 31, a flow rate setting unit 32, and a standby position setting unit 33. The control unit 31 controls the ultrasonic flow rate measurement unit 10, the flow rate adjustment unit 20, the flow rate setting unit 32, and the standby position setting unit 33.

[0043] The control unit 31 controls the flow rate adjustment unit 20 based on the liquid flow rate measurement value FRac measured by the ultrasonic flow rate measurement unit 10. The control unit 31 controls the flow rate adjustment unit 20 in either a flow rate adjustment mode or a standby mode.

[0044] When the flow rate adjustment mode is executed, the control unit 31 controls the flow rate adjustment unit 20 to move the valve body unit 21 to a target position that varies depending on the flow rate difference between the flow rate measurement value FRac and the flow rate set value FRset, so that the flow rate measurement value FRac of the liquid measured by the ultrasonic flow rate measurement unit 10 becomes the flow rate set value FRset set by the flow rate setting unit 32. When the standby mode is executed, the control unit 31 controls the flow rate adjustment unit 20 to move the valve body unit 21 to a standby position where the valve body unit 21 does not contact the valve hole 62, and then maintain the standby position.

[0045] The control unit 31 can instruct each of the upstream-side transducer 11 and the downstream-side transducer 12 included in the ultrasonic flow measurement unit 10 to emit an ultrasonic signal. The control unit 31 can also detect the timing at which an ultrasonic signal emitted from either the upstream-side transducer 11 or the downstream-side transducer 12 is received by the other one of the upstream-side transducer 11 and the downstream-side transducer 12.

[0046] The control unit 31 calculates a first propagation time from the timing of transmission of an ultrasonic signal instructed to the downstream transducer 12 and the corresponding timing of reception of the ultrasonic signal at the upstream transducer 11. The control device 30 also calculates a second propagation time from the timing of transmission of an ultrasonic signal instructed to the upstream transducer 11 and the corresponding timing of reception of the ultrasonic signal at the downstream transducer 12. The control unit 31 obtains the flow rate of the liquid flowing through the measurement flow path 14 based on a propagation time difference obtained by subtracting the second propagation time from the first propagation time and a predetermined flow rate calculation formula.

[0047] The flow rate setting unit 32 sets a flow rate set value FRset [ml / min] within a flow rate range from 0 [ml / min], which is the minimum flow rate, to FRmax [ml / min], which is the maximum flow rate of the flow control device 100. The flow rate setting unit 32 sets the flow rate set value FRset based on a flow rate setting signal that the control device 30 receives from the upper device 200 via the cable 101, for example.

[0048] The standby position setting unit 33 sets the standby position at a predetermined position between a closed position (lower limit position) corresponding to 0 (lower limit value), which is the minimum flow rate of the flow rate set value FRset that can be set by the flow rate setting unit 32, and an upper limit position corresponding to the maximum flow rate FRmax (upper limit value) of the flow rate set value FRset that can be set by the flow rate setting unit 32. The standby position is a position where the valve body unit 21 is placed on standby when the control unit 31 executes a standby mode, which will be described later.

[0049] The electric drive unit 22 of the flow rate adjustment unit 20 has a stepping motor 22a that moves the valve body unit 21 along the axis X1 by rotating around the axis X1, and a motor driver 22b that generates an excitation current that drives the stepping motor 22a and outputs it to the stepping motor 22a.

[0050] Fig. 4 is a longitudinal cross-sectional view showing the inlet-side channel section 50 and the pressure sensor 70 shown in Fig. 1. As shown in Figs. 1 and 4, the inlet-side channel section 50 is a member having an inlet-side inclined channel 51 formed therein that is inclined from the inlet port 100a toward the inlet channel 13 on the upstream side of the measurement channel 14 in a direction approaching the installation surface S. A pressure sensor 70 is attached to the inlet-side channel section 50 to detect the pressure of the liquid flowing through the inlet-side inclined channel 51.

[0051] As shown in FIGS. 1 and 3 , the outlet-side flow path section 60 is a component having an outlet-side inclined flow path 61 formed therein, which is inclined from the flow rate adjuster 20 toward the outlet port 100b and approaches the installation surface S. The outlet-side flow path section 60 guides the fluid from an opening 64 provided above the valve chamber 63 to the upstream side of the outlet-side inclined flow path 61 through an outlet flow path 65. The liquid guided to the upstream side of the outlet-side inclined flow path 61 is guided along the outlet-side inclined flow path 61 to the outlet port 100b. As shown in FIGS. 2 and 3 , the outlet-side flow path section 60 has through holes through which a plurality of fastening bolts 66 pass. The outlet-side flow path section 60 is fixed to the electric drive unit 22 by fastening the fastening bolts 66 to the electric drive unit 22.

[0052] The pressure sensor 70 measures the pressure (supply pressure) of the liquid flowing from the inlet port 100a into the inlet-side inclined flow path 51 on the upstream side of the measurement flow path 14. The pressure sensor 70 is, for example, a strain gauge type pressure sensor. As shown in FIG. 4, the pressure sensor 70 is attached to the inlet-side flow path section 50 by a sensor holder 71. A pressure signal indicating the pressure of the liquid measured by the pressure sensor 70 is transmitted to the control device 30 and stored in a memory section (not shown) provided in the control device 30. The pressure signal is also transmitted to the host device 200 via a cable 101.

[0053] Next, a flow control system 1 in which the flow control device 100 of this embodiment is installed will be described with reference to Fig. 6. Fig. 6 is a schematic configuration diagram showing the flow control system 1 in which the flow control device 100 is installed. As shown in Fig. 6, the flow control system 1 includes a pump 2 that pressure-feeds a liquid, a pipe 3 that transports the liquid from an inlet end 1a to an outlet end 1b, the flow control device 100, an on-off valve 4 arranged in the pipe 3 upstream of the flow control device 100, an on-off valve 5 arranged in the pipe 3 downstream of the flow control device 100, and a host device 200. The host device 200 is a device that controls the flow control device 100, the pump 2, the on-off valve 4, and the on-off valve 5.

[0054] The flow rate control system 1 uses a pump 2 to pump liquid flowing into a pipe 3 from an inlet end 1a, supplying the liquid to a flow rate control device 100, and supplies the liquid, the flow rate of which has been adjusted by the flow rate control device 100, to an outlet end 1b. An on-off valve 4 switches between a state in which liquid is supplied from the inlet end 1a to the flow rate control device 100 and a state in which it is not supplied. An on-off valve 5 switches between a state in which liquid is supplied from the flow rate control device 100 to the outlet end 1b and a state in which it is not supplied.

[0055] Fig. 7 is a block diagram showing the configuration of the host device 200. As shown in Fig. 7, the host device 200 has a flow rate adjustment control unit 210, a pump control unit 220 that controls the pump 2, and an on-off valve control unit 230 that controls the on-off valve 4 and the on-off valve 5. The flow rate adjustment control unit 210 has a mode transmission unit 211, a flow rate transmission unit 212, and a standby position transmission unit 213.

[0056] The mode transmission unit 211 transmits a first switching signal for switching the flow control device 100 from the standby mode to the flow control mode and a second switching signal for switching the flow control device 100 from the flow control mode to the standby mode to the flow control device 100 via the cable 101. The flow rate transmission unit 212 transmits a flow rate setting signal for setting a flow rate set value FRset to the flow control device 100 via the cable 101. The standby position transmission unit 213 transmits a standby position setting signal for setting a standby position to the flow control device 100 via the cable 101.

[0057] Next, the operation executed by the host device 200 of the flow rate adjusting system 1 will be described with reference to Fig. 8. Fig. 8 is a flowchart showing the operation executed by the host device 200.

[0058] In step S101, the flow rate adjustment control unit 210 determines whether to switch the flow rate control device 100 from standby mode to flow rate adjustment mode. If YES, the process proceeds to step S102, and if NO, the process of step S101 is repeated.

[0059] In step S102, the mode transmission unit 211 transmits to the flow control device 100 a first switching signal for switching the flow control device 100 from the standby mode to the flow control mode. In step S103, the flow rate transmitting unit 212 transmits to the flow control device 100 a flow rate setting signal for setting the flow rate setting value FRset.

[0060] In step S104, the on-off valve control unit 230 controls the on-off valve 4 on the upstream side of the flow control device 100 to be in an open state. In step S105, the on-off valve control unit 230 controls the on-off valve 5 downstream of the flow control device 100 to be in an open state.

[0061] In step S106, the pump control unit 220 starts the operation of the pump 2 and controls the pump 2 to operate at a desired rotation speed.

[0062] In step S107, the flow rate adjustment control unit 210 determines whether to switch the flow rate adjustment device 100 from the flow rate adjustment mode to the standby mode, and if YES, proceeds to the processing of step S108, and if NO, repeats the processing of step S107.

[0063] In step S108, the mode transmission unit 211 transmits to the flow control device 100 a second switching signal for switching the flow control device 100 from the flow control mode to the standby mode. In step S109, the standby position transmission unit 213 transmits to the flow control device 100 a standby position setting signal for setting a standby position where the valve body unit 21 is to be placed on standby when the flow control device 100 operates in the standby mode.

[0064] For example, the standby position transmission unit 213 preferably corrects the standby position setting signal so that the distance along the axis X1 from the valve hole 62 to the standby position increases as the temperature of the liquid supplied to the flow control device 100 increases. This is because the higher the temperature of the liquid, the more likely it is that the valve body unit 21 and the valve hole 62 will expand and come close to or come into contact with each other.

[0065] Furthermore, it is preferable that the standby position transmitter 213 corrects the standby position setting signal so that the distance along the axis X1 from the valve hole 62 to the standby position increases as the viscosity of the liquid supplied to the flow control device 100 increases, for example. This is because the flow rate of the liquid decreases as the viscosity of the liquid increases.

[0066] In step S110, the pump control unit 220 controls the pump 2 to stop its operation.

[0067] In step S111, the on-off valve control unit 230 controls the on-off valve 4 on the upstream side of the flow control device 100 to be in a closed state. In step S112, the on-off valve control unit 230 controls the on-off valve 5 downstream of the flow control device 100 to be in a closed state.

[0068] In step S113, the host device 200 determines whether to stop the flow rate adjusting system 1, and if YES, the process proceeds to step S114, and if NO, the process of step S101 is executed again.

[0069] In step S114, the upper level device 200 executes a stop process to stop each unit of the flow rate adjusting system 1, and ends the process of this flowchart.

[0070] Next, the processing executed by the flow control device 100 of this embodiment will be described with reference to Fig. 9. Fig. 9 is a flowchart showing the operation executed by the flow control device 100. It is assumed that the flow control device 100 is executing a standby mode before starting the operation shown in Fig. 9.

[0071] In step S201, the control unit 31 determines whether or not a first switching signal has been received from the higher-level device 200. If YES, the process proceeds to step S202, and if NO, the process of step S201 is repeated.

[0072] In step S202, the control unit 31 determines whether or not a flow rate setting signal has been received from the upper device 200. If YES, the process proceeds to step S203, and if NO, the process of step S202 is repeated.

[0073] In step S203, the control unit 31 controls the flow rate adjustment unit 20 to execute the flow rate adjustment mode. The flow rate setting unit 32 sets the flow rate set value FRset based on the flow rate setting signal transmitted from the higher-level device 200. When executing the flow rate adjustment mode, the control unit 31 controls the flow rate adjustment unit 20 to move the valve body unit 21 to a target position that varies depending on the flow rate difference between the flow rate measurement value FRac and the flow rate set value FRset, so that the flow rate measurement value FRac of the liquid measured by the ultrasonic flow measurement unit 10 becomes the flow rate set value FRset set by the flow rate setting unit 32.

[0074] In step S204, the control unit 31 determines whether or not a second switching signal has been received from the higher-level device 200. If YES, the process proceeds to step S205, and if NO, the process of step S204 is repeated.

[0075] In step S205, the control unit 31 determines whether or not a standby position setting signal has been received from the higher-level device 200. If YES, the process proceeds to step S206, and if NO, the process of step S205 is repeated.

[0076] In step S206, the control unit 31 controls the flow rate adjustment unit 20 to execute the standby mode. When executing the standby mode, the control unit 31 sets a standby position in the standby position setting unit 33 according to the standby position setting signal. Furthermore, the control unit 31 controls the flow rate adjustment unit 20 to move the valve body 21 to the standby position where the valve body 21 does not contact the valve hole 62, and then maintain the standby position.

[0077] In step S207, the control unit 31 determines whether or not to stop the flow control device 100. If YES, the control unit 31 ends the processing of this flowchart, and if NO, the control unit 31 executes step S201 again.

[0078] In the above flowchart, the control unit 31 advances the process to step S206 and executes the standby mode when it receives a standby position setting signal from the higher-level device 200, but other aspects are also possible. For example, even if it does not receive a standby position setting signal from the higher-level device 200 (for example, if it does not receive a standby position setting signal even after a predetermined time has passed), it may advance the process to step S206 and execute the standby mode.

[0079] 8 (processing to transmit a standby position setting signal). Also, the control unit 31 of the flow control device 100 sets a predetermined standby position in the standby position setting unit 33. In this way, when the flow control device 100 receives a standby position setting signal from the host device 200, it can set a standby position based on the standby position setting signal, and when the flow control device 100 does not receive a standby position setting signal from the host device 200, it can set a predetermined standby position.

[0080] Next, an example of a change in the opening degree of the valve body portion 21 will be described with reference to Fig. 10. Fig. 10 is a graph showing an example of a change in the opening degree of the valve body portion 21. In Fig. 10, the periods from time T0 to time T1, the period from time T2 to time T3, and the period from time T4 to time T5 are periods during which the flow control device 100 executes the standby mode. Also, in Fig. 10, the periods from time T1 to time T2 and the period from time T3 to time T4 are periods during which the flow control device 100 executes the flow control mode.

[0081] 10, an opening degree of the valve body portion 21 of 0% means that the valve body portion 21 is in contact with the valve hole 62, as shown by the solid line in FIG. 3. An opening degree of the valve body portion 21 of 100% means that the valve body portion 21 is in the position shown by the dashed line in FIG. 3.

[0082] When the control unit 31 of the flow control device 100 of this embodiment executes the flow control mode, the target position, which varies depending on the flow rate difference between the flow rate measurement value FRac and the flow rate set value FRset, is set between a lower limit position (a position where the opening of the valve body unit 21 is 0[%]) corresponding to the lower limit value of the flow rate set value FRset that the flow rate setting unit 32 can set, and an upper limit position (a position where the opening of the valve body unit 21 is 100[%]) corresponding to the upper limit value of the flow rate set value FRset that the flow rate setting unit 32 can set.

[0083] When the control unit 31 of the flow control device 100 of this embodiment executes the flow rate adjustment mode, the target position of the valve unit 21 is a position that varies depending on the flow rate difference between the flow rate measurement value FRac and the flow rate set value FRset. In the example shown in Fig. 10, in the flow rate adjustment mode executed between time T1 and time T2, the flow rate set value FRset is set so that the opening of the valve unit 21 is 20[%]. Also, in the flow rate adjustment mode executed between time T3 and time T4, the flow rate set value FRset is set so that the opening of the valve unit 21 is 40[%].

[0084] When the control unit 31 of the flow control device 100 of this embodiment executes the standby mode, the standby position at which the valve body unit 21 is located is a position set by the standby position setting unit 33, and is a position that is farther away from the valve hole 62 than the lower limit position. In the example shown in Fig. 10, the standby position setting unit 33 sets the standby position in the standby mode executed between time T0 and time T1 to a position with an opening degree of 10[%], the standby position in the standby mode executed between time T2 and time T3 to a position with an opening degree of 30[%], and the standby position in the standby mode executed between time T4 and time T5 to a position with an opening degree of 20[%].

[0085] As shown in FIG. 10, in order to set different standby positions for the standby mode executed between time T0 and time T1, the standby mode executed between time T2 and time T3, and the standby mode executed between time T4 and time T5, the standby position transmission unit 213 of the higher-level device 200 operates as follows.

[0086] The standby position transmission unit 213 transmits a standby position setting signal to the flow control device 100 so that the standby position in a predetermined standby mode varies according to the flow rate setting value FRset in a flow rate adjustment mode that is executed subsequent to the predetermined standby mode.

[0087] 10, the standby position in the standby mode from time T0 to time T1 is set to a position (position of 10% opening) where the opening is 10% lower than the flow rate set value FRset in the flow rate adjustment mode from time T1 to time T2 that is subsequently executed. Also, in the example shown in Fig. 10, the standby position in the standby mode from time T2 to time T3 is set to a position (position of 30% opening) where the opening is 10% lower than the flow rate set value FRset in the flow rate adjustment mode from time T3 to time T4 that is subsequently executed.

[0088] 10, the standby position setting unit 33 sets different standby positions for the standby mode executed between time T0 and time T1, the standby mode executed between time T2 and time T3, and the standby mode executed between time T4 and time T5, but other aspects are also possible. For example, the standby position setting unit 33 may set the standby position set in the standby mode to a predetermined fixed standby position (for example, a position at an opening degree of 10[%]).

[0089] [First Modified Example] In the embodiment described above, a modified example may be employed in which the standby position at which the valve body portion 21 is kept on standby in the standby mode of the flow control device 100 is corrected in accordance with the temperature of the liquid flowing through the flow control device 100.

[0090] Fig. 11 is a schematic configuration diagram showing a flow rate control system 1A according to a first modified example of the present invention. The flow rate control system 1A shown in Fig. 11 differs from the flow rate control system 1 shown in Fig. 6 in that it includes a temperature detection unit 6 that detects the temperature of the liquid flowing into the flow rate control device 100.

[0091] In the flow control system 1A according to the first modified example of the present invention, the standby position transmission unit 213 of the higher-level device 200 corrects the standby position setting signal so that the distance along the axis X1 from the valve hole 62 to the standby position becomes longer as the temperature of the liquid detected by the temperature detection unit 6 increases, and transmits the corrected standby position setting signal to the flow control device 100.

[0092] [Second Modification] In the embodiment described above, a modified example may be employed in which the standby position at which the valve body portion 21 is kept on standby in the standby mode of the flow control device 100 is corrected in accordance with the pressure of the liquid flowing through the flow control device 100.

[0093] Fig. 12 is a schematic configuration diagram showing a flow rate control system 1B according to a second modified example of the present invention. The flow rate control system 1B shown in Fig. 12 differs from the flow rate control system 1 shown in Fig. 6 in that it includes a pressure detection unit 7 that detects the pressure of the liquid flowing into the flow rate control device 100.

[0094] In the flow control system 1A according to the second modified example of the present invention, the standby position transmission unit 213 of the higher-level device 200 corrects the standby position setting signal so that the distance along the axis X1 from the valve hole 62 to the standby position becomes shorter as the pressure of the liquid detected by the pressure detection unit 7 increases, and transmits the corrected standby position setting signal to the flow control device 100.

[0095] [Third Modification] In the embodiment described above, a modified example may be employed in which the standby position at which the valve body portion 21 is kept on standby in the standby mode of the flow control device 100 is corrected in accordance with the pressure of the liquid flowing through the flow control device 100.

[0096] Fig. 13 is a schematic configuration diagram showing a flow control system 1C according to a third modified example of the present invention. The flow control system 1C shown in Fig. 1 includes a flow control device 100, a flow control device 100A, and a flow control device 100B. An on-off valve 4A is arranged between the pipe 3 and the flow control device 100A, and an on-off valve 4B is arranged between the pipe 3 and the flow control device 100B. An on-off valve 5A is arranged between the flow control device 100A and the outlet end 1bA, and an on-off valve 5B is arranged between the flow control device 100B and the outlet end 1bB.

[0097] The flow control device 100A adjusts the flow rate of the liquid supplied from the pipe 3 to the outlet end 1bA. The flow control device 100B adjusts the flow rate of the liquid supplied from the pipe 3 to the outlet end 1bB. When the pump 2 operates at a constant rotation speed, the larger the openings of the on-off valves 4A and 4B, the lower the pressure of the liquid supplied to the flow control device 100 via the on-off valve 4A. On the other hand, when the pump 2 operates at a constant rotation speed, the smaller the openings of the on-off valves 4A and 4B, the higher the pressure of the liquid supplied to the flow control device 100 via the on-off valve 4A.

[0098] In a flow control system 1C according to a third modified example of the present invention, the standby position transmission unit 213 of the host device 200 corrects the standby position setting signal so that the distance along the axis X1 from the valve hole 62 to the standby position in the flow control device 100 increases in response to an increase in the opening degrees of the on-off valves 4A and 4B, and transmits the corrected standby position setting signal to the flow control device 100. On the other hand, in the flow control system 1C, the standby position transmission unit 213 of the host device 200 corrects the standby position setting signal so that the distance along the axis X1 from the valve hole 62 to the standby position in the flow control device 100 decreases in response to a decrease in the opening degrees of the on-off valves 4A and 4B, and transmits the corrected standby position setting signal to the flow control device 100.

[0099] The actions and effects achieved by the flow control device 100 and the flow control system 1 of the present embodiment described above will be described.

[0100] According to the flow control device 100 of this embodiment, when switching from the flow control mode to the standby mode, the control unit 31 controls the flow control unit 20 to move the valve element 21 to a standby position where the valve element 21 does not contact the valve orifice 62 and then maintain the standby position. Because the standby position is a position where the valve element 21 does not contact the valve orifice 62, the valve element 21 has a larger opening than the fully closed position where the valve element 21 contacts the valve orifice 62. This improves the ability to track the flow rate set value FRset compared to when switching from the fully closed position to the flow control mode, preventing control delays. Even if the valve element 21 is excessively spaced from the valve orifice 62 and its opening is excessively large when switching from the flow control mode to the standby mode, the valve element 21 moves to the standby position and maintains the standby position. This prevents overshooting due to an excessive opening of the valve element 21 when switching from the standby mode to the flow control mode.

[0101] According to the flow control device 100 of this embodiment, the standby position is located farther from the valve hole 62 than the lower limit position, so that the flow rate setting value FRset follows the flow rate setting value FRset more accurately than when switching to the flow rate control mode from the lower limit position, thereby preventing control delays.

[0102] According to the flow control device 100 of this embodiment, by setting the standby position to a predetermined position between the lower limit position and the upper limit position by the standby position setting unit 33, it is possible to appropriately prevent overshoot and control delay from occurring when switching from the standby mode to the flow control mode.

[0103] According to the flow control device 100 of this embodiment, it is possible to appropriately switch between the flow control mode and the standby mode in response to the first switching signal and the second switching signal received from the higher-level device 200.

[0104] According to the flow control device 100 of this embodiment, the flow rate setting value FRset can be set based on the flow rate setting signal transmitted from the upper device 200, and the standby position can be set based on the standby position setting signal transmitted from the upper device 200.

[0105] According to the flow rate control system 1 of this embodiment, the standby position transmission unit 213 of the higher-level device 200 transmits a standby position setting signal to the flow rate control device 100 so that the standby position in a predetermined standby mode varies according to the flow rate set value FRset in the flow rate control mode that is executed subsequent to the predetermined standby mode. When switching from the predetermined standby mode to the flow rate control mode, the standby position becomes a position according to the flow rate set value FRset in the flow rate control mode, so that it is possible to appropriately prevent overshoot and control delays from occurring.

[0106] According to the flow control system 1A of the first variant of this embodiment, the distance along the axis X1 from the valve hole 62 to the standby position increases as the temperature of the liquid detected by the temperature detection unit 6 increases, and therefore, malfunctions caused by the valve body unit 21 and the valve hole 62 expanding as the temperature of the liquid increases and coming close to or into contact with each other can be appropriately prevented.

[0107] According to the flow control system 1B of the second variant of this embodiment, the distance along the axis from the valve hole to the standby position becomes shorter as the liquid pressure detected by the pressure detection unit 7 increases, thereby appropriately preventing the liquid flow rate from becoming excessive as the liquid pressure increases. [Explanation of symbols]

[0108] 1,1A,1B Flow Control System 1a Inlet end 1b Outflow end 2 pumps 3 Piping 4 On-off valve 5. On-off valve 6 Temperature detection unit 7 Pressure detection section 10 Ultrasonic flow rate measurement unit (flow rate measurement unit) 11 Upstream transducer 12 Downstream transducer 13 Inlet channel 14 Measurement flow path 15 Outlet channel 16,17 signal lines 20 Flow rate adjustment section 21 Valve body 22 Electric drive unit 30 Control device 31 Control Unit 32 Flow rate setting section 33 Standby position setting section 40 Housing section 50 Inlet flow path section 51 Inlet inclined channel 60 Outlet flow path section 61 Outflow side inclined channel 62 Valve orifice 63 Valve chamber 64 Opening 65 Outlet Channel 66 Fastening bolt 70 Pressure Sensor 100 Flow rate adjustment device 100a inlet port 100b Outlet Port 101 Cable 200 Upper device 210 Flow rate adjustment control unit 211 Mode Transfer Section 212 Flow rate transmission section 213 Standby position transmission unit 220 Pump control unit 230 On-off valve control section S installation surface X1,X2,Y axis

Claims

1. a flow rate measuring unit that measures the flow rate of a liquid flowing through the measurement flow path; a flow rate adjusting section that adjusts the flow rate of the liquid flowing out of the measurement flow channel by moving the valve body section along the axis in a direction toward or away from the valve hole; a flow rate setting unit that sets a flow rate setting value of the liquid adjusted by the flow rate adjusting unit; a control unit that controls the flow rate adjustment unit in either a flow rate adjustment mode or a standby mode, The control unit When the flow rate adjustment mode is executed, the flow rate adjustment unit is controlled to move the valve body unit to a target position that varies depending on a flow rate difference between the flow rate measurement value and the flow rate set value, so that the flow rate measurement value of the liquid measured by the flow rate measurement unit becomes the flow rate set value, and When the standby mode is executed, the flow rate control device controls the flow rate control unit to move the valve body to a standby position where the valve body does not contact the valve hole and then maintain the standby position.

2. the target position is set between a lower limit position corresponding to a lower limit value of the flow rate setting value that can be set by the flow rate setting unit and an upper limit position corresponding to an upper limit value of the flow rate setting value that can be set by the flow rate setting unit, The flow rate control device according to claim 1 , wherein the standby position is a position that is farther from the valve hole than the lower limit position.

3. The flow rate control device according to claim 2 , further comprising a standby position setting unit that sets the standby position at a predetermined position between the lower limit position and the upper limit position.

4. The flow control device according to claim 1 or 2, wherein the control unit switches the standby mode to the flow rate adjustment mode in response to receiving a first switching signal from a higher-level device that switches the standby mode to the flow rate adjustment mode, and switches the flow rate adjustment mode to the standby mode in response to receiving a second switching signal from the higher-level device that switches the flow rate adjustment mode to the standby mode.

5. the flow rate setting unit sets the flow rate setting value based on a flow rate setting signal for setting the flow rate setting value transmitted from the higher-level device; The flow rate control device according to claim 4 , wherein the control unit sets the standby position based on a standby position setting signal for setting the standby position transmitted from the host device.

6. A flow rate control system including a flow rate control device and a host device that controls the flow rate control device, The flow rate adjusting device is a flow rate measuring unit that measures the flow rate of a liquid flowing through the measurement flow path; a flow rate adjusting section that adjusts the flow rate of the liquid flowing out of the measurement flow channel by moving the valve body section along the axis in a direction toward or away from the valve hole; a flow rate setting unit that sets a flow rate setting value of the liquid adjusted by the flow rate adjusting unit; a control unit that controls the flow rate adjustment unit in either a flow rate adjustment mode or a standby mode, The control unit When the flow rate adjustment mode is executed, the flow rate adjustment unit is controlled to move the valve body unit to a target position that varies depending on a flow rate difference between the flow rate measurement value and the flow rate set value, so that the flow rate measurement value of the liquid measured by the flow rate measurement unit becomes the flow rate set value, and When executing the standby mode, the flow rate adjusting unit is controlled to move the valve body to a standby position where the valve body does not contact the valve hole, and then to maintain the standby position; The higher-level device is a mode transmitter that transmits to the flow rate control device a first switching signal that switches the flow rate control device from the standby mode to the flow rate control mode and a second switching signal that switches the flow rate control device from the flow rate control mode to the standby mode; a flow rate transmitting unit that transmits a flow rate setting signal for setting the flow rate setting value to the flow rate adjusting device; a standby position transmission unit that transmits a standby position setting signal to the flow rate control device to set the standby position, a flow control system in which the standby position transmission unit transmits the standby position setting signal to the flow control device so that the standby position in a predetermined standby mode varies depending on the flow rate setting value in the flow rate adjustment mode that is executed subsequent to the predetermined standby mode.

7. a temperature detection unit that detects the temperature of the liquid flowing through the flow rate control device; The flow control system according to claim 6, wherein the standby position transmission unit transmits the standby position setting signal to the flow control device so that the distance along the axis from the valve hole to the standby position increases in response to an increase in the temperature of the liquid detected by the temperature detection unit.

8. a pressure detection unit that detects the pressure of the liquid flowing into the flow rate control device; 7. The flow control system according to claim 6, wherein the standby position transmission unit transmits the standby position setting signal to the flow control device so that the distance along the axis from the valve hole to the standby position becomes shorter in response to an increase in the pressure of the liquid detected by the pressure detection unit.

9. A method for controlling a flow rate control device, comprising: The flow rate adjusting device is a flow rate measuring unit that measures the flow rate of a liquid flowing through the measurement flow path; a flow rate adjusting section that adjusts the flow rate of the liquid flowing out of the measurement flow channel by moving the valve body section along the axis in a direction toward or away from the valve hole; a flow rate setting unit that sets a flow rate setting value of the liquid adjusted by the flow rate adjusting unit, a flow rate adjusting step of controlling the flow rate adjusting unit to move the valve body unit to a target position that varies depending on a flow rate difference between the flow rate measurement value and the flow rate set value so that the flow rate measurement value of the liquid measured by the flow rate measuring unit becomes the flow rate set value; a standby process of moving the valve body portion to a standby position where the valve body portion does not contact the valve hole, and then controlling the flow rate adjustment unit to maintain the standby position.

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