Flow control device and method, and fluid supply system

Abstract

A flow control device according to an embodiment includes: a holding unit (101) that holds the opening characteristic of a flow control valve; an input unit (102) that inputs the target flow rate of the fluid flowing out of the flow control valve and the flow rate change speed until the target flow rate is reached; a detection unit (103) that detects the flow rate of the fluid flowing out of the flow control valve at a prescribed sampling period starting from the start of control of the target flow rate; and an opening adjustment unit (104) that adjusts the opening of the flow control valve. The opening adjustment unit (104) determines the difference between the detected flow rate by the detection unit (103) and a predetermined flow rate. When there is a difference, the opening corresponding to the predetermined flow rate is used as the adjusted opening and is calculated based on the Cv value of the opening characteristic, where the predetermined flow rate is a predetermined flow rate in the middle of the target flow rate corresponding to the detected flow rate and is determined according to the flow rate change speed and the number of detections by the detection unit (103). Then, the opening operation amount calculated based on the opening difference between the adjusted opening and the current opening of the flow control valve is used as the target value for opening control.

Description

Technical Field

[0001] The present invention relates to a flow control device and method for controlling the flow rate of a fluid discharged from a fluid machine such as a pump by a flow control valve, and a fluid supply system having the flow control device. Background Art

[0002] Conventionally, a flow control device for controlling the flow rate of a liquid discharged from a pump by a flow control valve has been known. In such a flow control device, generally, the difference between the detected flow rate from a flow meter disposed on the downstream side of the flow control valve and the target flow rate is calculated, and the opening degree of the flow control valve is controlled so as to eliminate the difference.

[0003] As the above-described flow control valve, valves having various configurations can be employed. The flow control valve has a relationship between the opening degree and the Cv value (capacity coefficient) called the opening characteristic, and such an opening characteristic varies depending on the valve configuration, for example. As representative opening characteristics, there are a linear characteristic, a quick opening characteristic, an equal percentage characteristic, and the like.

[0004] In the case where precise flow control is required, a flow control valve having a linear characteristic is preferably used. Here, when the flow control valve is a three-way valve, it is generally more difficult to achieve a linear characteristic than in the case of a two-way valve. In view of such a point, the applicant of the present application previously proposed a technique for improving the linear characteristic of a three-way valve in JP610443B. Summary of the Invention

[0005] For example, there is a system in which a liquid after temperature control is supplied from a flow control valve to a temperature control object and then the liquid is circulated. In such a system, for example, after temporarily stopping the system, when it is desired to slowly supply a low-temperature liquid to a high-temperature temperature control object at a certain ratio (i.e., linearly), considering the following situation: the liquid remaining in the temperature control object and becoming high temperature in the previous liquid supply rapidly returns to the system side due to the opening characteristic of the flow control valve. From the viewpoint of preventing thermal shock to the flow path, it is sometimes desired to avoid such a situation. That is, it is sometimes desired to make the flow rate stably change with a desired flow rate change.

[0006] However, even when a flow control valve called a linear characteristic is used in the above system, generally, there are sometimes some non-linear behaviors, and there are cases where it is difficult to make the flow rate change with a desired flow rate change. In addition, there are cases where a flow control valve having a non-linear characteristic needs to be used in the above system, but even in this case, as long as there is a concern about the above thermal shock, it is preferable to make the flow rate change with a desired flow rate change as much as possible.

[0007] The present invention has been completed in view of the above circumstances, and an object thereof is to provide a flow control device and method, and a flow supply system capable of stably changing the flow rate regardless of the opening characteristics of a flow control valve.

[0008] A flow control device according to an embodiment of the present invention controls the flow rate of a fluid flowing out of the flow control valve by changing the opening degree of the flow control valve. The flow control device includes: a holding unit that holds the opening characteristics of the flow control valve that determine the relationship between the opening degree and the Cv value of the flow control valve; an input unit that inputs a target flow rate of the fluid flowing out of the flow control valve and a flow rate change speed until the target flow rate is reached; a detection unit that detects the flow rate of the fluid flowing out of the flow control valve at a predetermined sampling period starting from the start of control of the target flow rate; and an opening degree adjustment unit that determines a difference between the detected flow rate detected by the detection unit and a predetermined flow rate. When there is such a difference, the opening degree corresponding to the predetermined flow rate is used as an adjustment opening degree, and an operation is performed based on the Cv value of the opening characteristics. By feedback control with the opening degree operation amount calculated based on the difference between the adjustment opening degree and the current opening degree of the flow control valve as a target value, the opening degree of the flow control valve is adjusted. The predetermined flow rate is a predetermined flow rate in the middle of the target flow rate corresponding to the detected flow rate, and the predetermined flow rate is determined based on the flow rate change speed and the number of detections by the detection unit.

[0009] Alternatively, the opening degree adjustment unit adjusts the opening degree of the flow control valve with the opening degree operation amount calculated based on the opening degree difference as a target value until the next flow rate detection by the detection unit. When the detection unit re-detects the flow rate, the opening degree operation amount is recalculated.

[0010] Alternatively, the opening degree adjustment unit calculates the opening degree operation amount by PID operation.

[0011] Alternatively, the flow control valve is a three-way valve.

[0012] Alternatively, the three-way valve has a receiving port, a supply port, and a bypass port. A flow control device according to an embodiment further includes a notification unit that, when changing the receiving port and the supply port from a cut-off state to a connected state, performs a notification for prompting the input of the target flow rate and the flow rate change speed.

[0013] Alternatively, the opening characteristics of the flow control valve are non-linear characteristics.

[0014] Alternatively, the flow control valve is configured to change the opening degree according to the rotation of a stepping motor, and the opening degree adjustment unit increases or decreases the drive pulses at each same time according to the opening degree operation amount.

[0015] In addition, the flow control method according to an embodiment of the present invention controls the flow rate of the fluid flowing out of the flow control valve by changing the opening degree of the flow control valve. Among them, the flow control method has the following steps: a determination step of determining the opening degree characteristic of the flow control valve that determines the relationship between the opening degree and the Cv value of the flow control valve; a decision step of determining the target flow rate of the fluid flowing out of the flow control valve and the flow rate change speed until the target flow rate is reached; a detection step of detecting the flow rate of the fluid flowing out of the flow control valve at a predetermined sampling period starting from the start of the control of the target flow rate; and an opening degree adjustment step of determining the difference between the detected flow rate detected by the detection unit and a predetermined flow rate. In the case where there is such a difference, the opening degree corresponding to the predetermined flow rate is used as the adjustment opening degree, and an operation is performed based on the Cv value of the opening degree characteristic. The opening degree operation amount calculated based on the opening degree difference between the adjustment opening degree and the current opening degree of the flow control valve is used as the target value to adjust the opening degree of the flow control valve. Here, the predetermined flow rate is a predetermined flow rate in the middle of the target flow rate corresponding to the detected flow rate, and the predetermined flow rate is determined according to the flow rate change speed and the number of detections in the detection step.

[0016] In addition, a fluid supply system according to an embodiment of the present invention includes: the above-mentioned flow control device; and a fluid circulation device having a fluid flow path provided with the flow control valve.

[0017] According to the present invention, regardless of the opening degree characteristic of the flow control valve, the flow rate can be stably changed. Brief Description of the Drawings

[0018] Figure 1 is a diagram showing a schematic structure of a cooler having a flow control device according to an embodiment of the present invention.

[0019] Figure 2 is a diagram showing Figure 1 a functional structure block diagram of the flow control device shown.

[0020] Figure 3 is a diagram showing Figure 1 the opening degree characteristic of the flow control valve provided in the cooler shown.

[0021] Figure 4 is a diagram showing Figure 1 an example of an input screen of the target flow rate and the flow rate change speed displayed on the display device of the flow control device shown.

[0022] Figure 5 is a flowchart for explaining Figure 1 an example of the operation of the flow control device shown. Detailed implementation mode

[0023] Hereinafter, the cooler 1 of the flow control device 100 having an embodiment of the present invention will be described. Figure 1 It is a diagram showing a schematic structure of the cooler 1 as an example of a fluid supply system.

[0024] <Overall structure of the cooler>

[0025] As Figure 1 shown, the cooler 1 has: a cooling flow path unit 10 having a cooling flow path 11, a heat exchanger 12, and a pump 13; a valve unit 20 having a flow rate regulating valve 21; and a flow control device 100. The valve unit 20 detachably connects the cooling flow path unit 10 to an external device 30 to be temperature-controlled. In the present embodiment, the cooling flow path unit 10 and the valve unit 20 constitute a fluid circulation device FS.

[0026] In the cooling flow path unit 10, a heat exchanger 12 and a pump 13 are arranged on the cooling flow path 11 through which a liquid as a fluid flows. When the pump 13 is driven, the liquid flows in the cooling flow path 11, and the liquid flows into the heat exchanger 12. The heat exchanger 12 in this example is connected to a refrigerator (not shown), and the flowing-in liquid is cooled by exchanging heat with the refrigerant that expands in the refrigerator. The liquid flowing in the cooling flow path unit 10 can be, for example, brine or other coolants.

[0027] When the cooler 1 is operating normally, the pump 13 is controlled so that the liquid flows at a constant flow rate.

[0028] The cooling flow path 11 has an upstream end 11A and a downstream end 11B, and the upstream end 11A and the downstream end 11B are detachably connected to the valve unit 20.

[0029] The valve unit 20 has a flow rate regulating valve 21 as a three-way valve, a receiving flow path 22, a supply flow path 23, a bypass flow path 24, and a return flow path 25.

[0030] The flow rate regulating valve 21 has a receiving port 21A, a supply port 21B, and a bypass port 21C, and can be switched to a "first state" in which the receiving port 21A and the supply port 21B are fully open-connected and the receiving port 21A and the bypass port 21C are cut off, and a "second state" in which the receiving port 21A and the supply port 21B are cut off and the receiving port 21A and the bypass port 21C are fully open-connected.

[0031] In addition, the state between the above-described first state and the second state is hereinafter referred to as the "intermediate state". In this intermediate state, the receiving port 21A is connected to the providing port 21B, and the receiving port 21A is connected to the bypass port 21C, and the liquid received by the receiving port 21A can be distributed to the providing port 21B and the bypass port 21C.

[0032] The flow rate regulating valve 21 has a stepping motor 21M as a driving part of the valve body, and adjusts the position of the valve body according to the rotation of the stepping motor 21M, thereby adjusting the opening degree between the receiving port 21A and the providing port 21B and the opening degree between the receiving port 21A and the bypass port 21C. In addition, the driving part of the valve body is not limited to the stepping motor 21M, and may be a solenoid or the like, for example.

[0033] The receiving flow path 22 detachably connects the downstream end 11B of the cooling flow path 11 and the receiving port 21A of the flow rate regulating valve 21.

[0034] The providing flow path 23 detachably connects the providing port 21B of the flow rate regulating valve 21 and the upstream side flow path 30A of the external device 30. A flow rate sensor 23S for detecting the flow rate of the liquid flowing in the providing flow path 23 is provided on the providing flow path 23.

[0035] The bypass flow path 24 detachably connects the bypass port 21C of the flow rate regulating valve 21 and the return flow path 25.

[0036] The return flow path 25 detachably connects the upstream end 11A of the cooling flow path 11 and the downstream side flow path 30B of the external device 30. The middle part of the bypass flow path 24 is connected to the return flow path 25, and the liquid can flow into the return flow path 25.

[0037] The external device 30 has an operation part 31 connected to the above-described upstream side flow path 30A and downstream side flow path 30B, and adjusts the temperature of the operation part 31 by using the liquid provided from the upstream side flow path 30A. Moreover, the downstream side flow path 30B allows the liquid flowing out from the operation part 31 to flow into the return flow path 25 of the valve unit 20.

[0038] The external device 30 in the present embodiment is, as an example, a film forming device which is a semiconductor manufacturing device. During normal film forming operation, the external device 30 adjusts the temperature of the wafer by using the provided liquid. On the other hand, the external device 30 is configured to perform internal cleaning when the film forming operation is stopped. When performing internal cleaning, the external device 30 stops the liquid supply from the valve unit 20 side and controls the inside to a high temperature state for internal cleaning.

[0039] The flow control device 100 can supply the liquid from the cooling flow path unit 10 only to the external device 30 by controlling the flow control valve 21 to the "first state" in which the receiving port 21A and the supply port 21B are fully open-connected and the receiving port 21A and the bypass port 21C are cut off. In addition, the flow control device 100 can circulate the liquid from the cooling flow path unit 10 through the valve unit 20 without supplying it to the external device 30 by controlling the flow control valve 21 to the "second state" in which the receiving port 21A and the supply port 21B are cut off and the receiving port 21A and the bypass port 21C are fully open-connected.

[0040] In addition, the flow control device 100 can supply a part of the liquid from the cooling flow path unit 10 to the external device 30 and make the other part flow into the bypass flow path 24 by controlling the flow control valve 21 to the "intermediate state". The flow control device 100 is electrically connected to the flow sensor 23S and the stepping motor 21M respectively, and controls the operation of the flow control valve 21 according to the detected flow rate from the flow sensor 23S. More specifically, the flow control device 100 changes the opening degree of the flow control valve 21 according to the detected flow rate from the flow sensor 23S, so that it can control the flow rate of the liquid flowing out from the supply port 21B and the flow rate of the liquid flowing out from the bypass port 21C. Hereinafter, the flow control device 100 will be described in detail.

[0041] <Flow control device>

[0042] The flow control device 100 is a controller for performing flow control, and can be constituted by a computer having a CPU, a ROM, etc., for example. In this case, according to the program stored in the ROM, it acquires the information from the flow sensor 23S and performs various processes such as sending a control signal to the stepping motor 21M. In addition, the flow control device 100 can also be constituted by other processors or circuits (such as FPGA (Field Programmable Gate Array), etc.).

[0043] Figure 2 is a block diagram showing the functional structure of the flow control device 100. As Figure 2 shown, the flow control device 100 has a holding unit 101, an input unit 102, a detection unit 103, an opening degree adjustment unit 104, and a notification unit 105. Among them, the holding unit 101 is constituted by a part of a storage unit such as a ROM, and the functional units other than the holding unit 101 are realized by executing the program stored in the storage unit such as a ROM.

[0044] The holding unit 101 holds the opening degree characteristics of the flow control valve 21 that determine the relationship between the opening degree of the flow control valve 21 and the Cv value (capacity coefficient).

[0045] Figure 3 Shows an example of the opening characteristic of the flow control valve 21 held by the holding unit 101. In Figure 3 , the horizontal axis represents the opening degree, and the vertical axis represents the Cv value. 0% marked on the horizontal axis means that the opening degrees of the receiving port 21A and the providing port 21B are 0%, that is, the receiving port 21A and the providing port 21B are fully closed. 100% marked on the horizontal axis means that the opening degrees of the receiving port 21A and the providing port 21B are 100%, that is, the receiving port 21A and the providing port 21B are fully open and connected. On the contrary, 0% marked on the horizontal axis means that the opening degrees of the receiving port 21A and the bypass port 21C are 100%, that is, the receiving port 21A and the bypass port 21C are fully open and connected. 100% marked on the horizontal axis means that the receiving port 21A and the bypass port 21C are fully closed.

[0046] In Figure 3 , the solid line indicated by the reference numeral Lp represents the relationship between the opening degree of the receiving port 21A and the providing port 21B and the Cv value. The double-dot dash line indicated by the reference numeral LB represents the relationship between the opening degree of the receiving port 21A and the bypass port 21C and the Cv value. In addition, the dotted line indicated by the reference numeral Lt represents the total Cv value. As Figure 3 shown, the opening characteristic of the flow control valve 21 in the present embodiment is a non-linear characteristic.

[0047] The opening degree for making the flow rate of the liquid flowing out of the flow control valve 21 a desired flow rate can be calculated using the Cv value. In the present embodiment, when controlling the flow rate of the liquid flowing out of the flow control valve 21 to a desired flow rate, the opening degree is determined according to the Cv value corresponding to the desired flow rate, and the flow control valve 21 is controlled toward the determined opening degree.

[0048] Return Figure 2 , the input unit 102 is used to input the target flow rate of the liquid flowing out of the flow control valve 21 and the flow rate change speed until the target flow rate is reached.

[0049] Specifically, the input unit 102 displays on a display device (not shown) a screen prompting the user to input the target flow rate of the liquid provided from the providing port 21B to the external device 30 and the flow rate change speed until the target flow rate of the liquid is reached. According to the user's input operation, the target flow rate and the flow rate change speed are input into the internal (storage unit, etc.) and held. In the present embodiment, liters per minute (L / min) is used as the unit of the target flow rate, and liters per minute 2 (L / min 2 ) is used as the unit of the flow rate change speed, but such units are not particularly limited.

[0050] Figure 4FIG. is an example of an input screen that shows the target flow rate and the flow rate change speed displayed on the display device by the flow control device 100 through the input unit 102. In Figure 4 The upper part of shows the input screen G1 for the target flow rate, and the lower part shows the input screen G2 for the flow rate change speed.

[0051] In the input screen G1 for the target flow rate, 10.0 L / min in the expression "STAGE FLOW SV (target flow rate): 10.0 L / min" represents the target flow rate. When the "update" is operated to change the target flow rate thus displayed, the target flow rate is updated. In the input screen G2 for the flow rate change speed, "RAMPING UP (increase): 5.0 L / min 2 " in the expression of 5.0 L / min 2 represents the flow rate change speed when increasing the flow rate provided to the external device 30. In addition, "RAMPING DOWN (decrease): 5.0 L / min 2 " in the expression of 5.0 L / min 2 represents the flow rate change speed when decreasing the flow rate provided to the external device 30. When the "update" is operated to change the flow rate change speed thus displayed, the flow rate change speed is updated. Hereinafter, the general term for the input screen G1 and the input screen G2 is referred to as the "ramp setting screen".

[0052] In addition, return Figure 2 , the detection unit 103 is electrically connected to the flow sensor 23S, and detects the flow rate of the liquid flowing out of the flow control valve 21 at a predetermined sampling period from the start of the control of the "target flow rate". In addition, the "target flow rate" mentioned here is the target flow rate input in the input screen G1 when increasing the flow rate provided to the external device 30. On the other hand, when decreasing the flow rate provided to the external device 30, for example, 0 L / min is set as the target flow rate.

[0053] Next, the opening degree adjustment unit 104 adjusts the opening degree of the flow control valve 21 through feedback control based on the detected flow rate detected by the detection unit 103, the target flow rate, and the flow rate change speed. In addition, hereinafter, when only the opening degree of the flow control valve 21 is described, this means the opening degrees of the receiving port 21A and the providing port 21B.

[0054] As a specific process, first, the opening degree adjustment unit 104 determines the difference between the detected flow rate detected by the detection unit 103 and a predetermined flow rate, where the predetermined flow rate is a predetermined flow rate in the middle of the target flow rate corresponding to the detected flow rate, and the predetermined flow rate is determined according to the flow rate change speed and the number of detections by the detection unit 103.

[0055] Next, in the case where there is a difference, the opening degree adjustment unit 104 calculates the opening degree corresponding to the above-mentioned predetermined flow rate based on the Cv value of the opening degree characteristic, and uses it as the adjusted opening degree.

[0056] Then, the opening degree adjustment unit 104 adjusts the opening degree of the flow rate adjustment valve 21 by feedback control with the opening degree operation amount calculated based on the opening degree difference between the calculated adjusted opening degree and the current opening degree of the flow rate adjustment valve 21 as the target value.

[0057] More specifically, the opening degree adjustment unit 104 adjusts the opening degree of the flow rate adjustment valve 21 with the opening degree operation amount calculated as above as the target value until the next flow rate detection by the detection unit 103. When the detection unit 103 re-performs the flow rate detection, the opening degree operation amount is recalculated.

[0058] However, it is also possible to perform the flow rate detection after the opening degree reaches the target value, and then calculate a new opening degree operation amount. In addition, in the present embodiment, the above-mentioned opening degree operation amount is calculated by PID operation. In addition, the "current opening degree of the flow rate adjustment valve 21" can be determined by an encoder or the like in the stepping motor 21M in the flow rate control device 100, or can be determined by holding the accumulated drive pulses.

[0059] In addition, when adjusting the opening degree, the opening degree adjustment unit 104 inputs the above-mentioned opening degree operation amount to the stepping motor 21M after converting it into drive pulses. At this time, the opening degree adjustment unit 104 increases or decreases the drive pulses at each same time according to the above-mentioned opening degree operation amount. Here, if the number of drive pulses at each time becomes too large, the stepping motor 21M may not be able to follow. Therefore, when the number of drive pulses at each time exceeds the upper limit value, the excess drive pulses can also be discarded to set the opening degree operation amount.

[0060] As described above, the opening degree adjustment unit 104 in the present embodiment does not perform feedback control corresponding to the difference between the detected flow rate and the final "target flow rate", but performs feedback control corresponding to the difference between the detected flow rate and the "predetermined flow rate" in the middle of the target flow rate, and calculates the opening degree operation amount in consideration of the opening degree characteristic of the flow rate adjustment valve 21. In this case, the flow rate of the liquid supplied from the flow rate adjustment valve 21 changes in a state close to the linear function V×t defined by the flow rate change speed V and the time t, and stably changes to the target flow rate.

[0061] On the other hand, when the communication unit 105 makes the reception port 21A and the supply port 21B transition from the cut-off state to the connected state, it performs a notification for prompting the input of the target flow rate and the flow rate change speed. Specifically, the communication unit 105 automatically displays Figure 4 the input screens G1 and G2 shown.

[0062] As described above, when the external device 30 performs internal cleaning, the liquid supply from the valve unit 20 side is stopped, and the interior (operating unit 31) is controlled to a high temperature state for internal cleaning. When the liquid supply from the valve unit 20 is restarted after the internal cleaning, if the liquid is suddenly supplied to the external device 30, the liquid remaining in the operating unit 31 of the external device 30 and being at a high temperature may suddenly return to the valve unit 20 and the cooling flow path unit 10 side, causing a thermal shock to them. To avoid such a situation, the notification unit 105 notifies the user to prompt the input of the target flow rate and the flow rate change speed.

[0063] <Action>

[0064] Next, with reference to Figure 5 An example of the operation of the flow rate control device 100 will be described.

[0065] Figure 5 It is a flowchart for explaining an example of the operation of the flow rate control device 100. The example of the operation described below is as follows: From the above-described second state (the state in which all the liquid is bypassed) until the state in which the liquid is supplied to the external device 30 at the target flow rate, the flow rate control valve 21 is controlled, and at this time, the flow rate control valve 21 changes the flow rate at the set flow rate change speed.

[0066] When an instruction for transferring the receiving port 21A and the supply port 21B from the cut-off state (i.e., the second state) to the connected state is generated, the operation shown in Figure 5 starts. At this time, first, the input unit 102 notifies the user to prompt the input of the target flow rate and the flow rate change speed, that is, displays the gradient setting screen (G1, G2) (step S1). When the gradient setting screen (G1, G2) is displayed, the user can input the target flow rate and the flow rate change speed.

[0067] Next, in step S2, the input unit 102 determines whether the target flow rate and / or the flow rate change speed have been changed. When the target flow rate and / or the flow rate change speed have not been changed, in step S3, the input unit 102 maintains the existing setting as it is. When the target flow rate and / or the flow rate change speed have been changed, in step S4, the input unit 102 changes the setting of the target flow rate and / or the flow rate change speed and holds it. In addition, in the present embodiment, even when the settings of the target flow rate and the flow rate change speed are maintained as the existing settings, if the operation screen is not operated, the process will not proceed. In addition, the processes of steps S2 to S4 can also be omitted by the user's selection.

[0068] Next, in step S5, the detection unit 103 detects (samples) the flow rate of the liquid flowing out of the flow rate control valve 21 (detected flow rate) based on the information from the flow rate sensor 23S.

[0069] Next, in step S6, the opening degree adjusting unit 104 determines whether the detected flow rate detected by the detection unit 103 has reached the target flow rate. Here, if it is determined that it has reached, the process ends; if it is determined that it has not reached, the process transfers to step S7.

[0070] Then, in step S7, the opening degree adjusting unit 104 determines the difference between the detected flow rate detected by the detection unit 103 and a predetermined flow rate, where the predetermined flow rate is a predetermined flow rate in the middle of the target flow rate corresponding to the detected flow rate, and the predetermined flow rate is determined according to the flow rate change speed and the number of detections of the detection unit 103. Here, for example, when the sampling period of the detection unit 103 is set to t (seconds) and the number of detections is the nth time, the predetermined flow rate can be calculated by multiplying the flow rate change speed by nt / 60.

[0071] Next, in step S8, when the difference is determined in step S7, the opening degree adjusting unit 104 calculates the opening degree (adjusting opening degree) corresponding to the above-mentioned predetermined flow rate according to the Cv value of the opening degree characteristic. On the other hand, when there is no difference in step S7, in this embodiment, the adjusting opening degree is not calculated. Then, when the opening degree adjusting unit 104 calculates the adjusting opening degree, it adjusts the opening degree of the flow rate control valve 21 by feedback control with the opening degree operation amount calculated based on the opening degree difference between the adjusting opening degree and the current opening degree of the flow rate control valve 21 as the target value. On the other hand, when the adjusting opening degree is not calculated, the opening degree adjusting unit 104 performs feedback control with the opening degree operation amount set to 0. Then, after the opening degree adjusting unit 104 supplies the opening degree operation amount to the flow rate control valve 21, the process returns to step S5.

[0072] The flow rate control device 100 of the present embodiment described above does not perform feedback control corresponding to the difference between the detected flow rate and the target flow rate, but performs feedback control corresponding to the difference between the detected flow rate and the "predetermined flow rate" in the middle of the target flow rate, and calculates the opening degree operation amount in consideration of the opening degree characteristic of the flow rate control valve 21. Hereinafter, the flow rate control method of such a present embodiment will be described by steps.

[0073] First, a determination process is performed to determine the opening characteristic of the flow control valve 21 that determines the relationship between the opening of the flow control valve 21 and the Cv value. Next, a decision process is performed to determine the target flow rate of the liquid flowing out of the flow control valve 21 and the flow rate change speed until the target flow rate is reached. Next, a detection process is performed to detect the flow rate of the liquid flowing out of the flow control valve 21 at a prescribed sampling period starting from the control of the target flow rate. Next, an opening adjustment process is performed to determine the difference between the detected flow rate detected by the detection process and the predetermined flow rate. In the case where there is a difference, the opening corresponding to the predetermined flow rate is used as the adjustment opening, and an operation is performed based on the Cv value of the opening characteristic. The opening operation amount calculated based on the opening difference between the adjustment opening and the current opening of the flow control valve 21 is used as the target value to adjust the opening of the flow control valve 21, where the predetermined flow rate is the predetermined flow rate in the middle of the target flow rate corresponding to the detected flow rate, and the predetermined flow rate is determined based on the flow rate change speed and the number of detections in the detection process.

[0074] According to such an embodiment of the present invention, the flow rate of the liquid supplied from the flow control valve 21 can be linearly changed to the target flow rate in accordance with the set flow rate change speed. Therefore, regardless of the opening characteristic of the flow control valve 21, the flow rate can be stably changed.

[0075] In addition, in this embodiment, the opening adjustment unit 104 adjusts the opening of the flow control valve 21 with the calculated opening operation amount as the target value until the next flow rate detection by the detection unit 103. In the case where the detection unit 103 performs a new flow rate detection, the opening operation amount is recalculated. In this case, the operation of the flow control valve 21 can be made smooth, so that a sharp change in the flow rate can be effectively suppressed.

[0076] In addition, in this embodiment, the above-mentioned opening operation amount is calculated by PID operation. As a result, the operation of the flow control valve 21 can also be made smooth, so that a sharp change in the flow rate can be effectively suppressed.

[0077] The embodiments of the present invention have been described above, but the present invention is not limited to the embodiments described above, and various changes can be made to the above embodiments. For example, the flow control device 100 in the above embodiment is applied to the flow control of a liquid, but the flow control device 100 can also be applied to, for example, the flow control of the gas discharged by a blower. In addition, in the above embodiment, an example in which the opening characteristic of the flow control valve 21 is a non-linear characteristic has been described, but the opening characteristic of the flow control valve 21 is not particularly limited, and the present invention is an effective technology in any case of the opening characteristic.

Claims

1. A flow control device that controls the flow rate of fluid flowing out of the flow control valve by changing the opening degree of the flow control valve, wherein, the flow control device includes: a holding unit that holds the opening degree characteristic of the flow control valve that determines the relationship between the opening degree of the flow control valve and the Cv value; an input unit that inputs the target flow rate of the fluid flowing out of the flow control valve and the flow rate change speed until reaching the target flow rate; a detection unit that detects the flow rate of the fluid flowing out of the flow control valve at a prescribed sampling period starting from the start of control of the target flow rate; and an opening degree adjustment unit that determines the difference between the detected flow rate detected by the detection unit and a predetermined flow rate. When there is such a difference, the opening degree corresponding to the predetermined flow rate is used as the adjusted opening degree, and an operation is performed based on the Cv value of the opening degree characteristic. By performing feedback control with the opening degree operation amount calculated based on the difference between the adjusted opening degree and the current opening degree of the flow control valve as the target value, the opening degree of the flow control valve is adjusted. Here, the predetermined flow rate is a predetermined flow rate in the middle of the target flow rate corresponding to the detected flow rate, and the predetermined flow rate is determined based on the flow rate change speed and the number of detections by the detection unit.

2. The flow control device according to claim 1, wherein, the opening degree adjustment unit adjusts the opening degree of the flow control valve with the opening degree operation amount calculated based on the opening degree difference as the target value until the next flow rate detection by the detection unit. When the detection unit re - performs flow rate detection, the opening degree operation amount is recalculated.

3. The flow control device according to claim 1, wherein, the opening degree adjustment unit calculates the opening degree operation amount through PID operation.

4. The flow control device according to claim 1, wherein, the flow control valve is a three - way valve.

5. The flow control device according to claim 4, wherein, the three - way valve has a receiving port, a supply port, and a bypass port, and the flow control device further includes a notification unit that, when transferring the receiving port and the supply port from the cut - off state to the connected state, performs a notification for prompting the input of the target flow rate and the flow rate change speed.

6. The flow control device according to claim 1, wherein, the opening degree characteristic of the flow control valve is a non - linear characteristic.

7. The flow control device according to claim 1, wherein, the flow control valve is configured to change the opening degree according to the rotation of a stepping motor, and the opening degree adjustment unit increases or decreases the drive pulses per the same time according to the opening degree operation amount.

8. A flow control method that controls the flow rate of fluid flowing out of the flow control valve by changing the opening degree of the flow control valve, wherein, the flow control method includes the following steps: a determination step of determining the opening degree characteristic of the flow control valve that determines the relationship between the opening degree of the flow control valve and the Cv value; a decision step of determining the target flow rate of the fluid flowing out of the flow control valve and the flow rate change speed until reaching the target flow rate; A detection process that starts from the control of the target flow rate and detects the flow rate of the fluid flowing out of the flow rate regulating valve at a prescribed sampling period; and An opening degree adjustment process that determines the difference between the detected flow rate detected by the detection process and a predetermined flow rate. When there is such a difference, the opening degree corresponding to the predetermined flow rate is taken as the adjusted opening degree, and an operation is performed based on the Cv value of the opening degree characteristic. The opening degree operation amount calculated based on the difference between the adjusted opening degree and the current opening degree of the flow rate regulating valve is taken as the target value to adjust the opening degree of the flow rate regulating valve. Here, the predetermined flow rate is a predetermined flow rate in the middle of the target flow rate corresponding to the detected flow rate, and the predetermined flow rate is determined based on the flow rate change speed and the number of detections in the detection process.

9. A fluid supply system, wherein the fluid supply system includes: the flow rate control device according to claim 1; and a fluid flow device having a fluid flow path provided with the flow rate regulating valve.

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