JP2009265859A - Flow controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow controller controlling a flow rate in a wide range without significantly increasing cost. <P>SOLUTION: A flow control system 10 has: a flow sensor 14 detecting the flow rate of a liquid medicine; and a pilot regulator 20 as a flow control means and a first opening/closing valve 40 permitting or prohibiting passage of a fluid provided in parallel with each other downstream of the flow sensor 14. A downstream end part of a discharge pipe 13 on downstream side of the flow sensor 14 is connected to a first branch pipe 15 and a second branch pipe 16. The first branch pipe 15 is provided with the pilot regulator 20, and the second branch pipe 16 is provided with the first opening/closing valve 40. A controller 30 drives an electropneumatic regulator 18 and a first solenoid valve 19 based on a flow rate value detected by the flow sensor 14 and a target flow rate value, and executes flow rate feedback control such that the fluid flow rate coincides with the target flow rate value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flow rate control device that controls the flow rate of a fluid.

2. Description of the Related Art As a flow control device, there is known a device that adjusts a flow rate while performing flow rate feedback control so that an actual flow rate of a fluid flowing through a fluid control valve matches a target value. In this case, a flow sensor is provided upstream or downstream of the fluid control valve, and the valve opening of the fluid control valve is controlled based on the actual flow detected by the flow sensor so that the actual flow matches the target value. (For example, Patent Document 1). Here, as a field where flow control with high accuracy is particularly required, there are a semiconductor manufacturing field, a chemical field, a chemical field, and the like. In the flow control device used in such a field, the flow path is formed of a material having high chemical stability such as fluororesin, or the valve portion is formed of the same kind of resin with a diaphragm that can be isolated from the chemical. Or
Japanese Patent No. 3623125

  However, if it is intended to control the flow rate over a wide range in the above flow control device, it is necessary to increase the size of a diaphragm made of a high-cost material such as a fluororesin excellent in chemical resistance, resulting in a significant cost increase. . Further, when the diaphragm or the like is enlarged, there may occur a problem that the pressure resistance or reliability of the diaphragm film is lowered.

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a flow rate control device capable of controlling the flow rate over a wide range without significantly increasing the cost.

  In order to solve the above-described problems, a flow control device according to the present invention includes a fluid passage that allows fluid to flow, a regulator that is provided in the fluid passage and adjusts the flow rate of the fluid that flows through the fluid passage, and the fluid passage. And a bypass passage that bypasses the regulator, and an opening adjustment section that is provided in the bypass passage and adjusts the opening of the bypass passage.

  According to the present invention, since the bypass passage that bypasses the regulator is provided in the fluid passage, the fluid can be passed through the fluid passage on the regulator side and also through the bypass passage. As a result, it is possible to circulate a large flow rate fluid that exceeds the flow rate range that can be controlled by the regulator. Since the opening adjustment unit is provided in the bypass passage, the flow rate of the fluid flowing through the bypass passage can be increased or decreased by adjusting the opening of the bypass passage by the opening adjustment unit. Thus, the flow rate of the fluid flowing through the fluid passage on the regulator side can be adjusted. Therefore, the fluid flow rate can be controlled over a wide range.

  Conventionally, when controlling the flow rate over a wide range, it has been necessary to increase the size of a diaphragm made of a fluororesin or the like having a high material unit price, and thus a significant increase in cost could not be avoided. In that respect, since the flow rate control device of the present invention has a configuration in which a bypass passage having an opening degree adjusting unit is provided for the fluid passage, the flow rate can be controlled over a wide range without a significant increase in cost. it can.

  The opening degree adjusting unit is preferably an opening / closing unit that switches the bypass passage between an open position and a closed position. According to this, since the bypass passage can be switched between the open position and the closed position by the opening / closing portion, both the fluid passage and the bypass passage on the regulator side can be obtained by setting the bypass passage to the open position by the opening / closing portion. The fluid can be circulated in the tank. On the other hand, if the bypass passage is set to the closed position by the opening / closing portion, the fluid can be circulated only to the fluid passage on the regulator side. The flow rate of the fluid flowing through the fluid passage on the regulator side can be adjusted by the regulator. Thereby, the (overall) flow rate of the fluid can be controlled over a wide range. In addition, since the opening / closing section switches the bypass passage between the open position and the closed position, it is generally less expensive than a regulator or the like that can adjust the opening of the flow path. Therefore, the flow rate can be controlled over a wide range while further suppressing the increase in cost. Furthermore, since the two-position switching type opening / closing part is excellent in terms of responsiveness, when the flow rate is changed by opening / closing the opening / closing part, the flow rate can be stabilized at the target flow rate value after the change in a short time. There are also advantages.

  Note that if the flow rate feedback control is performed so that the fluid flow rate is matched with the target flow rate value while being detected by a flow rate sensor or the like, the flow rate of the fluid flowing through the bypass passage without the regulator is pulsated by the water pump. Even if it fluctuates due to the influence of the above, the entire flow rate can be converged to the target flow rate value by controlling the flow rate of the fluid flowing through the fluid passage on the regulator side so as to cancel the variation.

  When the opening / closing part is in the open position, it is preferable that the flow rate of the fluid flowing through the bypass passage is equal to or less than the maximum value of the flow rate that can be controlled by the regulator.

  When the opening / closing part is in the closed position (hereinafter referred to as a small flow rate), the fluid flows only through the fluid passage on the regulator side, so the flow rate of the fluid is continuously controlled within a range that can be controlled by the regulator. Therefore, the maximum value of the flow rate that can be controlled at a small flow rate is the maximum value of the flow rate that can be controlled by the regulator (hereinafter referred to as the regulator-side maximum value). On the other hand, when the opening / closing part is in the open position (hereinafter referred to as a large flow rate), the fluid flows not only through the regulator-side fluid passage but also through the bypass passage (specifically, when the fluid flows only through the bypass passage). Therefore, the flow rate of the fluid is continuously controlled in a range of the sum of the flow rate in the range controllable by the regulator and the flow rate of the fluid flowing through the bypass passage (hereinafter referred to as bypass flow rate). Therefore, the minimum value of the flow rate that can be controlled at the time of a large flow rate is the flow rate value when the fluid flows only through the bypass passage, that is, the bypass flow rate value.

  If the minimum flow rate that can be controlled at high flow rate (bypass flow rate value) is greater than the maximum flow rate that can be controlled at low flow rate (regulator side maximum value), set the flow rate between these values. Therefore, the flow rate cannot be controlled continuously. In that respect, according to the present invention, when the opening / closing part is in the open position, the flow rate of the fluid flowing through the bypass passage (that is, the bypass flow rate) is less than or equal to the maximum flow rate that can be controlled by the regulator (that is, the regulator-side maximum value). Therefore, there is an uncontrollable flow rate range between the minimum flow rate value at the low flow rate (minimum control flow rate value) and the maximum flow rate value at the high flow rate (maximum control flow rate value). There is no. Thereby, it becomes possible to control the flow rate of the fluid over a wide range from the minimum control flow rate value to the maximum control flow rate value.

  It is preferable that a plurality of the bypass passages are provided in the fluid passage, and that the opening degree adjusting unit is provided in each of the bypass passages.

  According to this, since a plurality of bypass passages are provided in the fluid passage, the fluid can be circulated through the regulator-side fluid passage and also through each bypass passage. This makes it possible to circulate a large flow rate of fluid. Since each opening passage is provided with an opening degree adjustment unit, the flow rate of the fluid flowing through each bypass passage is adjusted by adjusting the opening degree of each bypass passage by the opening degree adjustment unit. In addition, the flow rate of the fluid flowing through the fluid passage on the regulator side can be adjusted by the regulator. As a result, the flow rate of the fluid can be controlled over a wider range.

  Further, if the opening / closing part in the second invention is used as the opening degree adjusting part provided in each bypass passage, and the flow rate of the fluid flowing through each bypass passage is set to be equal to or less than the maximum value of the flow rate that can be controlled by the regulator. Thus, the flow rate of the fluid can be controlled in a wider range and continuously without a significant increase in cost, and control with excellent responsiveness can be performed.

  The flow rate control device includes a controller that controls the regulator and the opening degree adjusting unit, and the controller closes the bypass passage when a target flow rate value is equal to or less than a maximum flow rate that can be controlled by the regulator. It is preferable to control the opening degree adjusting unit so that the bypass passage is opened when the target flow rate value is larger than the maximum flow rate controllable by the regulator.

  According to this, a regulator and an opening degree adjustment part can be controlled by a controller. Further, when the target flow rate value set by the user or the like is less than or equal to the maximum flow rate that can be controlled by the regulator, the bypass passage can be closed by controlling the opening degree adjusting unit by the controller. On the other hand, when the target flow rate value is larger than the maximum value of the flow rate that can be controlled by the regulator, the bypass adjuster can open the bypass passage. Accordingly, the bypass passage can be automatically opened and closed according to the target flow rate value, and the flow rate can be automatically controlled over a wide range, so that the convenience of the user can be improved.

  In particular, fields in which high-precision flow rate control is required include the semiconductor manufacturing field, the chemical field, and the chemical field. In the flow control device used in such a field, chemical resistance is required, and generation of dust due to sliding of the valve body portion must be avoided. Therefore, the regulator used in such a field is arranged in the inflow port into which the fluid flows in, the outflow port in which the fluid flows out, the flow path from the inflow port to the outflow port, and in the middle of the flow path. A body body having a valve seat portion formed therein, a valve body built in the body body and seated on or separated from the valve seat portion, and provided on one end side in the displacement direction of the valve body. An urging portion that urges the body toward the valve seat portion, and the valve seat portion that is provided on the other end side in the displacement direction of the valve body and resists the urging force of the urging portion. The operation portion that controls the pressure of the fluid by adjusting the pressing force and the flow path and the accommodating region of the urging portion are partitioned and integrated with the valve body. The first diaphragm, and the flow path and the operation section are partitioned A second diaphragm that are integrated into Rutotomoni the valve body preferably includes a.

  According to this, in the regulator, the valve body is seated on the valve seat portion formed in the middle of the flow path from the inlet to the outlet in the body body, and the flow path is closed or separated from the valve seat. The flow rate and pressure of the fluid are controlled by opening the path. Specifically, the valve body is urged toward the valve seat portion by the urging portion to be seated on the valve seat portion, and is separated from the valve seat portion against the urging force by the urging portion by the operation portion. It is separated from the valve seat portion by being pressed to the side. Moreover, the first diaphragm and the second diaphragm are integrated with the valve body, and these diaphragms partition the flow path from the accommodating region of the urging unit and the operation unit, respectively. As a result, it is possible to eliminate or reduce a portion that slides due to the displacement of the valve body, and therefore it is possible to eliminate or reduce a factor that reduces the purity of the fluid such as generation of particles.

  Further, since the diaphragm is a part that is always in contact with the chemical solution, it is preferably formed of a material having excellent chemical resistance such as a fluororesin. Thereby, it can avoid that a diaphragm is corroded by a chemical | medical solution.

  On the other hand, in the on-off valve in which the opening / closing part is built and the flow path that connects the fluid inlet and outlet is formed, a biasing part that constantly biases the opening / closing part toward the closed position; A pressing portion that can be switched between a pressing state in which the opening / closing portion is pressed toward an open position against a biasing force by the biasing portion and a release state in which the pressing state is released; and the flow path on the pressing portion side It is preferable that an opening / closing diaphragm that is partitioned from the space and integrated with the opening / closing portion is provided. Thereby, also in the on-off valve, like the regulator, the part that slides due to the displacement of the on-off portion is eliminated in the flow path.

  The opening / closing diaphragm is preferably formed of a material having excellent chemical resistance such as a fluororesin, like the diaphragm in the regulator. Thereby, it can avoid that the opening-and-closing diaphragm is corroded by a chemical | medical solution.

  As described above, the regulator and the on-off valve are provided with a diaphragm formed of fluororesin or the like, thereby eliminating or reducing factors that lower the purity of the fluid, such as generation of particles as a whole flow control device. In addition, the diaphragm can be avoided from being corroded by the chemical solution.

(First embodiment)
Hereinafter, an embodiment embodying a flow rate control system used for supplying chemicals in a semiconductor production line will be described with reference to the drawings. FIG. 1 is a circuit diagram showing an overall configuration of a chemical solution supply circuit including a flow rate control system.

  As shown in FIG. 1, the circuit is provided with a chemical pump 11 for sucking and discharging chemical liquid. The chemical pump 11 is composed of, for example, a diaphragm pump or a bellows pump. The chemical liquid stored in the chemical liquid tank X is sucked by the chemical liquid pump 11 through the suction pipe 12 constituting the chemical liquid suction passage.

  A discharge pipe 13 constituting a chemical liquid discharge pipe is connected to the discharge side of the chemical liquid pump 11. A flow rate control system 10 as a flow rate control unit is provided on the downstream side of the discharge pipe 13. The chemical liquid discharged from the chemical liquid pump 11 is discharged to the wafer 36 as a use point through the flow rate control system 10. Therefore, the chemical solution is controlled to a predetermined flow rate in the flow rate control system 10 and is discharged onto the wafer 36.

  The flow rate control system 10 includes a flow rate sensor 14 that detects the flow rate of the chemical solution, a pilot regulator 20 that is provided in parallel with each other on the downstream side, and a first on-off valve 40 that permits or prohibits passage of fluid. And are provided. The downstream end of the discharge pipe 13 on the downstream side of the flow sensor 14 is connected to a first branch pipe 15 and a second branch pipe 16, of which a pilot regulator 20 is provided in the first branch pipe 15, A first on-off valve 40 is provided in the two-branch pipe 16. Each of the branch pipes 15 and 16 is connected to the collective pipe 17 at the downstream end, and the downstream end of the collective pipe 17 serves as a discharge nozzle 17 a that discharges the chemical liquid to the wafer 36.

  Next, the configuration of the pilot regulator 20 and the first on-off valve 40 will be briefly described with reference to FIGS. 2 is a longitudinal sectional view showing the configuration of the pilot regulator, and FIG. 3 is a longitudinal sectional view showing the configuration of the on-off valve.

  First, the configuration of the pilot regulator 20 will be described.

  The pilot regulator 20 is provided with a suction passage 21 for sucking fluid and a discharge passage 22 for discharging fluid. A through hole serving as a valve chamber 23 communicating with each of the passages 21 and 22 is formed in a substantially central portion of the pilot regulator 20 so as to extend in the vertical direction. The valve chamber 23 has a small hole diameter at a substantially central portion in the vertical direction. In other words, the inner wall surface of the valve chamber 23 protrudes toward the axial line side of the valve chamber 23 in the central portion, and the protruding portion serves as the valve seat portion 25. The valve chamber 23 has an upstream valve chamber 23a below the valve seat 25 and a downstream valve chamber 23b above the valve seat 25. More specifically, the upper end of the downstream valve chamber 23 b is a circular passage 23 c having a large hole diameter, and the circular passage 23 c communicates with the discharge passage 22.

  The valve chamber 23 accommodates a valve body 24 that can reciprocate in the axial direction of the through hole. The valve body 24 includes two diaphragm members 26 and 27, and each diaphragm member 26 and 27 is made of, for example, a fluororesin. The lower diaphragm member 26 includes a rod portion 28 extending in the vertical direction, and a diaphragm portion 29 that is integrated and connected at the lower end portion of the rod portion 28. An enlarged diameter portion 28 a having an enlarged cross-sectional area is formed at a substantially central portion in the vertical direction of the rod portion 28. Since the upper end portion of the enlarged diameter portion 28 a is formed larger than the inner diameter of the valve chamber 23 in the valve seat portion 25, the upper end portion of the enlarged diameter portion 26 a comes into contact with the valve seat portion 25. . Therefore, when the valve body 24 moves upward, the upper end portion of the enlarged diameter portion 28a comes into contact with the valve seat portion 25, and the communication between the suction passage 21 and the discharge passage 22 is blocked, while the valve body 24 is moved downward. When moved, the upper end portion of the enlarged diameter portion 28a is separated from the valve seat portion 25, and the suction passage 21 and the discharge passage 22 are communicated with each other.

  A spring accommodating chamber 31 is formed on the opposite side of the valve chamber 23 across the diaphragm portion 29. A compression coil spring 32 is accommodated in the spring accommodating chamber 31. The upper end portion of the compression coil spring 32 is in contact with the lower end portion of the valve body 24, and the valve body 24 is constantly urged upward by the urging force of the compression coil spring 32. As a result, the state in which the upper end portion of the enlarged diameter portion 28 a of the rod portion 28 is in contact with the valve seat portion 25 is maintained.

  A pressure operation chamber 33 into which operation air is introduced from the outside is formed on the opposite side of the valve chamber 23 across the upper diaphragm member 27. The pressure operation chamber 33 is communicated with an air introduction port 34, and operation air supplied from an electropneumatic regulator 18 (see FIG. 1) described later is supplied to the pressure operation chamber 33 via the air introduction port 34. When the operation air is supplied to the pressure operation chamber 33, the valve body 24 is displaced downward according to the operation pressure of the operation air.

  In the pilot regulator 20 configured as described above, in an initial state where the operation pressure is not applied to the pressure operation chamber 33, the upper end portion of the enlarged diameter portion 28 a of the rod portion 28 is caused to be the valve seat portion 25 by the urging force of the compression coil spring 32. The communication between the upstream valve chamber 23a and the downstream valve chamber 23b is blocked. Thereby, the flow of fluid from the suction passage 21 to the discharge passage 22 is blocked. On the other hand, when operating air is supplied to the pressure operation chamber 33, the valve body 24 is displaced downward against the urging force of the compression coil spring 32, and the upstream valve chamber 23a and the downstream valve chamber 23b are moved to each other. Communicated. Thereby, the flow of fluid from the suction passage 21 to the discharge passage 22 is allowed. Further, when the operation pressure in the pressure operation chamber 33 is increased or decreased, the upper end portion of the enlarged diameter portion 28 a of the rod portion 28 is separated from the valve seat portion 25 or close to the valve seat portion 25. As a result, the flow rate of the fluid flowing from the upstream valve chamber 23a to the downstream valve chamber 23b is increased or decreased.

  Next, the configuration of the first on-off valve 40 will be described.

  The first on-off valve 40 is configured by an air operated valve that is opened and closed by air pressure. The first on-off valve 40 is formed with a cylindrical cylinder 41 extending in the vertical direction. A piston rod 42 is accommodated in the cylinder 41. The piston rod 42 has a large diameter portion 42 a and a lower diameter portion 42 b and is slidably accommodated in the cylinder 41.

  A spring accommodating chamber 43 is formed above the piston rod 42. A compression coil spring 44 is accommodated in the spring accommodating chamber 43. The lower end portion of the compression coil spring 44 is in contact with the upper end portion of the piston rod 42. As a result, the piston rod 42 is constantly urged downward by the urging force of the compression coil spring 44.

  A pressure control chamber 45 is provided below the large diameter portion 42 a of the piston rod 42. The pressure control chamber 45 communicates with the air introduction port 46. Operation air supplied from a first solenoid valve 19 (see FIG. 1) described later is supplied to the pressure control chamber 45 via an air introduction port 46. When operating air is supplied to the pressure control chamber 45, the piston rod 42 moves upward against the biasing force of the compression coil spring 44.

  A diaphragm valve body 47 is integrally provided at the lower end portion of the piston rod 42. The diaphragm valve body 47 is made of, for example, a fluororesin.

  The first on-off valve 40 is provided with a suction passage 48 for sucking fluid and a discharge passage 49 for discharging fluid. A valve chamber 51 communicating with the cylinder 41 is formed in a circular groove shape below the cylinder 41, and the suction passage 48 and the discharge passage 49 are communicated with each other through the valve chamber 51. The suction passage 48 opens to the valve chamber 51 as a valve hole 48 a in the central portion of the valve chamber 51, and the periphery of the opening portion is a valve seat portion 52. The lower end portion of the diaphragm valve body 47 is in contact with the valve seat portion 52, and the diaphragm valve body 47 is in a closed position in which the lower end portion contacts the valve seat portion 52 and an open position in which the lower end portion is separated from the valve seat portion 52. Is switched between two positions.

  In the first on-off valve 40 configured as described above, when the operation air is not supplied to the pressure control chamber 45, the diaphragm valve body 47 is biased downward by the compression coil spring 44, and the lower end of the diaphragm valve body 47. The portion is in the closed position where it abuts against the valve seat portion 52. In this case, the communication between the suction passage 48 and the valve chamber 51 is blocked, and the flow of fluid through the valve chamber 51 is prevented. On the other hand, when operating air is supplied to the pressure control chamber 45 through the air introduction port 46, the diaphragm valve body 47 moves upward against the biasing force of the compression coil spring 44, and the lower end portion of the diaphragm valve body 47 is The open position is separated from the valve seat portion 52. As a result, the suction passage 48 and the valve chamber 51 communicate with each other, and fluid flow through the valve chamber 51 is allowed.

  Returning to the description of FIG. 1, an electropneumatic regulator 18 and a first electromagnetic valve 19 as air supply means are connected to the pilot regulator 20 and the first on-off valve 40 configured as described above, respectively.

  The electropneumatic regulator 18 is connected to the air introduction port 34 of the pilot regulator 20. The electropneumatic regulator 18 has a configuration capable of arbitrarily adjusting the operating air pressure, and the air pressure in the pressure operating chamber 33 of the pilot regulator 20 is adjusted by adjusting the operating air pressure.

  On the other hand, the first electromagnetic valve 19 is connected to the air introduction port 46 of the first on-off valve 40. The first electromagnetic valve 19 opens or closes in response to energization to supply or shut off air to the pressure control chamber 45 of the first on-off valve 40. That is, the first opening / closing valve 40 is configured to be opened / closed by opening / closing the first electromagnetic valve 19. When the supply of air to the pressure control chamber 45 is stopped, the pressure control chamber 45 is released from the pressurized state, for example, opened to the atmosphere.

  The flow control system 10 includes a controller 30. The controller 30 is an electronic control device mainly composed of a microcomputer including a CPU and various memories. In addition to the flow rate setting command value (target flow rate value) being input to the controller 30 from a management computer that manages and manages this system, the fluid flow rate detected by the flow rate sensor 14 is sequentially input. The controller 30 drives the electropneumatic regulator 18 and the first electromagnetic valve 19 based on these inputs, and performs flow rate feedback control so that the fluid flow rate Q matches the target flow rate value.

  The controller 30 outputs a closing command signal to the first solenoid valve 19 when the flow rate setting command value is equal to or less than the maximum control flow rate value (for example, 5.0 L / min) of the pilot regulator 20, and the first electromagnetic The valve 19 is closed. Thereby, supply of the operation air to the pressure control chamber 45 of the 1st on-off valve 40 is stopped, and the 1st on-off valve 40 is closed. As a result, the fluid flows only through the first branch pipe 15. In this case, the flow rate of the fluid flowing through the first branch pipe 15 (hereinafter referred to as the first flow rate Q1) becomes the fluid flow rate Q as it is. In addition, when the 1st on-off valve 40 is in a closed state, the closed state of the 1st solenoid valve 19 is maintained, and by extension, the closed state of the 1st on-off valve 40 is also maintained.

  The controller 30 calculates a deviation between the target flow rate value input from the management computer and the actual flow rate Q (= Q1) detected by the flow sensor 14, and performs arithmetic processing such as PID calculation based on the deviation, A command signal is output to the electropneumatic regulator 18. The electropneumatic regulator 18 adjusts the operating air pressure based on a command signal from the controller 30 and supplies the adjusted operating air to the pressure operating chamber 33 of the pilot regulator 20. By repeatedly executing such processing, the fluid flow rate Q (= Q1) is converged to the target flow rate value.

  On the other hand, when the flow rate setting command value (target flow rate value) is larger than the maximum control flow rate value of the pilot regulator 20, the controller 30 outputs an opening command signal to the first electromagnetic valve 19, and the first electromagnetic valve 19 To release. As a result, operating air is supplied to the pressure control chamber 45 of the first on-off valve 40 and the first on-off valve 40 is opened. As a result, the fluid flows through the first branch pipe 15 and the second branch pipe 16. Therefore, the fluid flow rate Q is a combined flow rate of the first flow rate Q1 and the flow rate of the fluid flowing through the second branch pipe 16 (hereinafter referred to as the second flow rate Q2) (Q = Q1 + Q2).

  The controller 30 performs calculation processing such as PID calculation based on the target flow rate value and the actual flow rate Q, and outputs a command signal to the electropneumatic regulator 18 as described above. From the electropneumatic regulator 18, operating air whose pressure is adjusted based on the command signal is supplied to the pilot regulator 20. As a result, the first flow rate Q1 is controlled, and consequently the fluid flow rate Q is controlled. That is, according to this flow rate feedback control, even if the second flow rate Q2 fluctuates due to the influence of the pulsation of the chemical pump 11, etc., the fluid flow rate Q is targeted by controlling the first flow rate Q1 so as to cancel the fluctuation. The flow rate can be converged.

  Next, the operation when the flow rate control is performed in the flow rate control system 10 will be described based on the time chart shown in FIG. In this description, it is assumed that the maximum control flow rate by the pilot regulator 20 and the control flow rate by the first on-off valve 40 are set to 5 L / min and 10 L / min, respectively.

  As shown in FIG. 4, when a flow rate value of 5 L / min is first input from the management computer as a flow rate setting command value (target flow rate value) to the controller 30 at the timing t1, the flow rate is supplied from the controller 30 to the electropneumatic regulator 18. An open command signal corresponding to the value is output. Based on this command signal, the operation air whose pressure is adjusted according to the set flow rate value (5 L / min) is supplied from the electropneumatic regulator 18 to the pressure operation chamber 33 of the pilot regulator 20. As a result, the valve body 24 of the pilot regulator 20 is displaced upward according to the pressure value adjusted, and the upstream side and the downstream side of the pilot regulator 20 are communicated with each other. As a result, the fluid starts to flow through the first branch pipe 15, and the flow rate is controlled so that the flow rate becomes the set flow rate of 5 L / min. Since the flow rate setting command value (5 L / min) is equal to or lower than the maximum control flow rate value (5 L / min) by the pilot regulator 20 at the timing t1, the first on-off valve 40 is kept closed. Therefore, the fluid flows only through the first branch pipe 15.

  When the target flow rate value is changed from 5 L / min to 15 L / min at timing t <b> 2, the target flow rate value becomes larger than the maximum control flow rate value by the pilot regulator 20, so that the controller 30 sends an opening command signal to the first solenoid valve 19. Is output, and the first electromagnetic valve 19 is opened. As a result, operating air is supplied to the pressure control chamber 45 of the first on-off valve 40, and the first on-off valve 40 is opened. As a result, the fluid flows through the first branch pipe 15 and the second branch pipe 16. Specifically, since the control flow rate by the first on-off valve 40 is set to 10 L / min, the fluid flows through the second branch pipe 16 at a flow rate of 10 L / min (the on-off valve portion in FIG. 4) and On the one-branch pipe 15 side, the flow rate is controlled so that the flow rate is 5 L / min (for the pilot regulator in FIG. 4). As a result, the entire circuit is controlled so that the fluid flow rate becomes the target flow rate value of 15 L / min.

  According to the configuration of the present embodiment described in detail above, the following excellent effects can be obtained.

  The flow rate control system 10 includes a flow rate sensor 14 that detects a flow rate of fluid, and a pilot regulator 20 and a first regulator 20 that are respectively disposed on a first branch pipe 15 and a second branch pipe 16 that are provided in parallel with each other on the downstream side. An on-off valve 40 is provided. As a result, if the first on-off valve 40 is opened, the fluid can be circulated through the second branch pipe 16, so that a large amount of fluid exceeding the maximum control flow rate of the pilot regulator 20 can be circulated. Further, the flow rate of the fluid flowing through the first branch pipe 15 can be adjusted by the pilot regulator 20. Therefore, the fluid flow rate can be controlled over a wide range.

  Conventionally, when the flow rate is controlled over a wide range, it is necessary to enlarge the diaphragm members 26 and 27 made of fluororesin having a high material unit price, and thus it has been impossible to avoid a significant increase in cost. In this respect, the present flow control system 10 is a system that can be configured by a combination of existing general-purpose members including the second branch pipe 16 serving as a bypass passage and the first on-off valve 40 that opens and closes the second branch pipe 16. The flow rate can be controlled over a wide range without increasing the flow rate.

  Furthermore, when the flow rate control is performed over a wide range, it is necessary to enlarge the body of the pilot regulator 20 together with the enlargement of the diaphragm members 26 and 27, so there is a concern that the accuracy of the flow rate control is lowered. In this respect, the flow control system 10 has a configuration that does not involve an increase in the size of the body of the pilot regulator 20, so that the flow rate can be controlled over a wide range without a decrease in the accuracy of the flow control.

  The first on-off valve 40 that opens and closes the second branch pipe 16 is constituted by a two-position switching type air operated valve. Thereby, compared with the case where the 1st on-off valve 40 is comprised with the regulator etc. which can adjust flow volume and are generally expensive, cost reduction can be aimed at.

  The controller 30 performs flow rate feedback control by driving the electropneumatic regulator 18 and the first electromagnetic valve 19 based on the flow rate detected by the flow rate sensor 14 and the flow rate setting command value. Thereby, the flow rate can be controlled with high accuracy.

(Second Embodiment)
Next, a second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment. FIG. 5 is a circuit diagram showing the overall configuration of the chemical solution supply circuit including the flow rate control system according to the present embodiment. In this figure, members corresponding to those in FIG. .

  The flow control system 60 in the present embodiment includes a flow sensor 14 and a pilot regulator 20, a first on-off valve 40, and a second on-off valve 61 provided in parallel with each other on the downstream side of the flow sensor 14. In other words, the flow control system 60 is obtained by further providing the second open / close valve 61 in parallel with the pilot regulator 20 and the first open / close valve 40 in the flow control system 10 in the first embodiment. A third branch pipe 62 is connected to the downstream end of the discharge pipe 13 together with the first branch pipe 15 and the second branch pipe 16, and a second on-off valve 61 is provided in the third branch pipe 62. Yes. The downstream end of each branch pipe 15, 16, 62 is connected to the collecting pipe 17, and the downstream end of the collecting pipe 17 serves as a discharge nozzle 17 a that discharges the chemical liquid to the wafer 36. The second on-off valve 61 is constituted by an air operated valve having the same configuration and specifications as the first on-off valve 40, for example.

  A second electromagnetic valve 63 is connected to the second on-off valve 61 (the air introduction port 46). The second electromagnetic valve 63 has, for example, the same configuration as the first electromagnetic valve 19. The second electromagnetic valve 63 opens or closes in response to energization, thereby supplying or shutting off the operating air to the pressure control chamber 45 of the second on-off valve 61. Thereby, the diaphragm valve body 47 of the second on-off valve 61 is switched between the open position and the closed position, and the flow of the fluid is permitted or prohibited.

  In addition to the flow rate setting command value (target flow rate value) being input to the controller 30 as described above, the fluid flow rate detected by the flow rate sensor 14 is sequentially input. The controller 30 drives the electropneumatic regulator 18 and the electromagnetic valves 19 and 63 on the basis of these inputs, and performs flow rate feedback control similar to that in the first embodiment.

  In addition, when the flow rate setting command value (target flow rate value) is larger than the maximum control flow rate of the pilot regulator 20, the controller 30 outputs an opening command signal to the electromagnetic valves 19 and 63, Let open. Specifically, when the flow rate setting command value is larger than the maximum control flow rate of the pilot regulator 20 and less than the sum of the maximum control flow rate of the pilot regulator 20 and the control flow rate of the on-off valve 40 (or 61). Then, the first electromagnetic valve 19 is opened. In this case, the first on-off valve 40 is opened. On the other hand, when the flow rate setting command value is larger than the sum of the maximum control flow rate value of the pilot regulator 20 and the control flow rate of the on-off valve 40 (or 61), both solenoid valves 19 and 63 are opened. In this case, both on-off valves 40 and 61 are opened.

  Next, the operation when the flow rate control is performed in the flow rate control system 60 will be described based on the time chart shown in FIG. In this description, it is assumed that the maximum control flow rate of the pilot regulator 20 and the control flow rates of the on-off valves 40 and 61 are each set to 5 L / min.

  As shown in FIG. 6, when a flow rate value of 5 L / min is first input from the management computer as a flow rate setting command value (target flow rate value) to the controller 30 at timing t11, the flow rate is supplied from the controller 30 to the electropneumatic regulator 18. An open command signal corresponding to the value is output. Based on this command signal, the operation air whose pressure is adjusted according to the set flow rate value (5 L / min) is supplied from the electropneumatic regulator 18 to the pressure operation chamber 33 of the pilot regulator 20. As a result, the valve body 24 of the pilot regulator 20 is displaced downward according to the pressure value adjusted, and the upstream side and the downstream side of the pilot regulator 20 are communicated. As a result, the fluid starts to flow through the first branch pipe 15, and the flow rate is controlled so that the flow rate becomes the set flow rate of 5 L / min. Since the flow rate setting command value (5 L / min) is the same value as the maximum control flow rate value (5 L / min) by the pilot regulator 20 at the timing t11, the first on-off valve 40 and the second on-off valve 61 remain closed. To do. Therefore, the fluid flows only through the first branch pipe 15.

  When the target flow rate value is changed from 5 L / min to 10 L / min at timing t12, the target flow rate value is larger than the maximum control flow rate (5 L / min) of the pilot regulator 20, and the maximum control flow rate of the pilot regulator 20 is reached. And the control flow rate of the on-off valve 40 (or 61) is equal to or less than the sum (10 L / min), so that the controller 30 controls the first electromagnetic valve 19 to be opened, and as a result, the first on-off valve 40 is opened. . Accordingly, the fluid flows through the first branch pipe 15 and the second branch pipe 16. Specifically, since the control flow rate by the first on-off valve 40 is set to 5 L / min, the fluid flows through the second branch pipe 16 at a flow rate of 5 L / min (for the first on-off valve in FIG. 6). On the first branch pipe 15 side, the flow rate is controlled so that the flow rate becomes 5 L / min (for the pilot regulator in FIG. 6). As a result, the flow rate of the entire circuit is controlled so that the fluid flow rate becomes the target flow rate value of 10 L / min.

  When the target flow rate value is changed from 10 L / min to 15 L / min at timing t13, the target flow rate value is the sum (10 L / min) of the maximum control flow rate of the pilot regulator 20 and the control flow rate of the on-off valve 40 (or 61). ), The second electromagnetic valve 63 is opened while the first electromagnetic valve 19 is kept open. As a result, the second on-off valve 61 is opened while the open state of the first on-off valve 40 is maintained. As a result, the fluid flows through the first branch pipe 15 and the second branch pipe 16 and also flows through the third branch pipe 62. Specifically, since the control flow rates of the on-off valves 40 and 61 are set to 5 L / min, the fluid flows through the second branch pipe 16 and the third branch pipe 62 at a flow rate of 5 L / min (the first flow in FIG. 6). The flow rate is controlled so that the flow rate is 5 L / min (for the pilot regulator in FIG. 6) on the first branch pipe 15 side. As a result, the flow rate of the entire circuit is controlled so that the fluid flow rate becomes the target flow rate value of 15 L / min.

  According to the configuration of the present embodiment described in detail above, the following excellent effects can be obtained.

  The flow control system 60 includes a first branch pipe 15 provided in parallel with each other on the downstream side of the flow sensor 14, and a second branch pipe 16 and a third branch pipe 62 as bypass passages. Accordingly, the fluid can be circulated through the first branch pipe 15 and through the second branch pipe 16 and the third branch pipe 62. Thereby, the fluid of a large flow volume can be distribute | circulated compared with the flow control system 10 in 1st Embodiment. Further, since the first branch valve 16 and the second branch valve 61 are provided in the second branch pipe 16 and the third branch pipe 62, respectively, the branch pipes 16, 61 are opened and closed by opening and closing the valve 40, 61. The flow of the fluid in the first branch pipe 15 can be permitted or prohibited, and since the pilot regulator 20 is provided in the first branch pipe 15, the flow rate of the fluid flowing through the first branch pipe 15 can be adjusted. Thereby, compared with the case where flow control is performed by the flow control system 10 in the first embodiment, flow control can be performed over a wider range.

  The control flow rate of each on-off valve 40, 61 was set to the same value as the maximum control flow rate of the pilot regulator 20. As a result, the flow rate can be controlled to 0 to 5 L / min (by the pilot regulator 20) when both the on-off valves 40 and 61 are closed, and the first on-off valve 40 is open and the second on-off valve 61 is closed. Sometimes the flow rate can be controlled to 5 to 10 L / min, and when both the on-off valves 40 and 61 are opened, the flow rate can be controlled to 10 to 15 L / min. Therefore, since the flow rate can be continuously controlled in the range of 0 to 15 L / min, the flow rate can be controlled in a wide range and continuously.

(Other embodiments)
The present invention is not limited to the above embodiments, and may be implemented as follows, for example.

  (1) In the above embodiment, the flow sensor 14 is provided on the upstream side of the pilot regulator 20 and the on-off valves 40, 61. However, the flow sensor 14 is provided on the downstream side of the pilot regulator 20 and the on-off valves 40, 61, that is, collective piping. 17 may be provided.

  (2) In the above embodiment, the pilot regulator 20 and the on-off valves 40 and 61 are arranged in parallel with each other on the downstream side of the flow sensor 14, but a plurality of pilot regulators 20 are connected to each other on the downstream side of the flow sensor 14. It is good also as a structure arrange | positioned in parallel. If it does so, it will become possible to control the flow volume of the fluid which distribute | circulates each branch piping 15,16,62, respectively. However, in consideration of the fact that the pilot regulator 20 is generally more expensive than the on-off valves 40 and 61, it is desirable that the pilot regulator 20 has a configuration using inexpensive on-off valves 40 and 61.

  (3) In the above embodiment, one or two on-off valves 40 and 61 are arranged in parallel with the pilot regulator 20 on the downstream side of the flow rate sensor 14, but three or more on-off valves are in parallel with the pilot regulator 20. 40 and 61 may be arranged. By doing so, it becomes possible to control the flow rate over a wider range.

  (4) In the above-described embodiment, the pilot regulator 20 and the on-off valves 40 and 61 are configured as separate bodies, but they may be configured to be integrated. Then, since the flow control systems 10 and 60 can be configured in a compact manner, it is possible to contribute to simplification of the line when incorporated in a production line or the like.

  (5) In the above-described embodiment, the case where the flow rate control system 10 is used for supplying a chemical solution in a semiconductor manufacturing line has been described as an example. May be. For example, it can be used in a chemical production line or a chemical product production line.

  (6) In the second embodiment, the flow rate setting command value is larger than the maximum control flow rate of the pilot regulator 20, and is not more than the sum of the maximum control flow rate of the pilot regulator 20 and the on-off valve 40 (or 61). In this case, the first on-off valve 40 is controlled to be opened, but the second on-off valve 61 may be controlled to be opened. Further, the first on-off valve 40 and the second on-off valve 61 may be controlled to be opened alternately. By doing so, the use load of each of the on-off valves 40 and 61 can be leveled, so that a situation in which the life of one of the on-off valves 40 and 61 is significantly reduced can be avoided.

The circuit diagram which shows the whole structure of a chemical | medical solution supply circuit provided with a flow control system. The longitudinal cross-sectional view which shows the structure of a pilot regulator. The longitudinal cross-sectional view which shows the structure of an on-off valve. The time chart which shows the effect | action of the flow control performed by a flow control system. The circuit diagram which shows the whole structure of a chemical | medical solution supply circuit provided with the flow control system in 2nd Embodiment. The time chart which shows the effect | action of the flow control performed by the flow control system in 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Flow control system as a flow control apparatus, 11 ... Chemical liquid pump, 13 ... Discharge piping as a fluid passage, 14 ... Flow sensor, 15 ... 1st branch piping as a fluid passage, 16 ... 2nd branch as a bypass passage Piping, 18 ... electro-pneumatic regulator, 19 ... first solenoid valve, 20 ... pilot regulator as regulator, 30 ... controller, 40 ... first opening / closing valve as opening adjustment section and opening / closing section, 60 ... as flow control device A flow rate control system, 61 ... a second opening / closing valve as an opening degree adjusting part and an opening / closing part, 62 ... a third branch pipe as a bypass passage, 63 ... a second electromagnetic valve.

Claims (5)

A fluid passage through which fluid flows;
A regulator that adjusts the flow rate of the fluid that is provided in the fluid passage and flows through the fluid passage;
A bypass passage provided in the fluid passage and bypassing the regulator;
A flow rate control device comprising: an opening degree adjusting unit that is provided in the bypass passage and adjusts the opening degree of the bypass passage.   The flow rate control device according to claim 1, wherein the opening degree adjustment unit is an opening / closing unit that switches the bypass passage between an open position and a closed position.   The flow rate control device according to claim 2, wherein the flow rate of the fluid flowing through the bypass passage when the opening / closing portion is in the open position is equal to or less than a maximum value of the flow rate that can be controlled by the regulator.   4. The flow rate control device according to claim 1, wherein a plurality of the bypass passages are provided in the fluid passage, and the opening degree adjusting unit is provided in each of the bypass passages. 5.   A controller for controlling the regulator and the opening adjustment unit; the controller closes the bypass passage when the target flow rate value is less than or equal to the maximum flow rate controllable by the regulator, and the target flow rate value is The flow rate control device according to any one of claims 1 to 4, wherein the opening degree adjusting unit is controlled so that the bypass passage is opened when the flow rate is greater than a maximum value that can be controlled by the regulator.

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