Butterfly valve device system

Abstract

To provide a butterfly type valve device system capable of suppressing an increase in manufacturing cost and achieving high reliability by reliably maintaining airtightness when fully closed.SOLUTION: A butterfly valve 26 which is supported by a valve shaft 25 so as to be openable and closable in a valve hole 23 and is biased to an open side by a biasing member 31, and in which a peripheral edge is brought into contact with an inner peripheral surface of the valve hole 23 via a seal member 27 at a fully closed position, a drive mechanism 22 which rotates the valve shaft 25 by a drive force of a motor 30, an opening degree detection unit which detects an opening degree of the butterfly valve 26, and a drive mechanism which drives the butterfly valve 26 to a closed side against the biasing member 31 according to an increase in a drive current to the motor 30; When the butterfly valve 26 is driven to the fully closed position, the control part increases a drive current to the motor 30 to a crushing current value higher than a control fully closed current value required for driving to the fully closed position.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a butterfly valve arrangement system. [Background technology]

[0002] For example, Patent Document 1 discloses a butterfly-type vacuum pressure control device used in semiconductor manufacturing processes. This vacuum pressure control device is disposed between a vacuum vessel and a vacuum pump, and can connect or disconnect the vacuum vessel and the vacuum pump in response to the opening and closing of a butterfly valve element supported on a rotating shaft within a valve hole. To maintain airtightness when fully closed, an annular elastic rubber seal is fitted within the valve hole, and a cam mechanism presses the periphery of the butterfly valve element against the valve seat of this elastic seal.

[0003] Specifically, the butterfly valve element is supported so that it can rotate around the rotation axis and also move linearly. A cam member of the cam mechanism is fixed on the butterfly valve element, and as the rotation axis rotates in the reverse direction -K, the cam member abuts against a backing plate, causing the butterfly valve element to move linearly and press the periphery against the valve seat made of elastic sealing material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-19851 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the vacuum pressure control device of Patent Document 1 requires a complex structure such as a cam mechanism to move the butterfly valve element in a straight line, which increases manufacturing costs and makes the operation less reliable, which may result in an inability to maintain airtightness when the valve is closed, posing a reliability problem.

[0006] The present invention has been made to solve these problems, and its purpose is to provide a butterfly valve device system that can suppress increases in manufacturing costs and achieves high reliability by reliably maintaining airtightness when fully closed. [Means for solving the problem]

[0007] In order to achieve the above object, the butterfly valve device system of the present invention comprises: a butterfly valve that is supported by a valve stem within a valve hole so as to be able to open and close, and is biased to the open side by a biasing member, and in the fully closed position, its periphery abuts against the inner surface of the valve hole via a resilient sealing member; a drive mechanism connected to the valve stem and rotates the valve stem by the driving force of a motor; an opening detection unit that detects the opening of the butterfly valve; and a control unit that supplies a driving current to the motor and drives the butterfly valve to the closed side against the biasing member as the driving current increases, and controls the opening of the butterfly valve based on the opening detected by the opening detection unit and a target opening, and is characterized in that when the butterfly valve is driven to the fully closed position, the control unit increases the driving current to the motor to a collapse current value that is higher than the control fully closed current value required to drive the butterfly valve to the fully closed position.

[0008] In another aspect, the control unit may increase the drive current to the motor from the control fully closed current value to the collapse current value, and then maintain the drive current at the collapse current value.

[0009] In another aspect, the control unit may increase the drive current to the motor from the control fully closed current value to the collapse current value, and then decrease the drive current to the control fully closed current value.

[0010] In another aspect, the control unit may increase the drive current to the motor from the control fully closed current value to the collapse current value, and then alternately switch between the control fully closed current value and the collapse current value.

[0011] In another aspect, the device may further include a deterioration degree determination unit that determines the deterioration of the sealing member over time, and a collapse current value correction unit that corrects the collapse current value based on the deterioration over time determined by the deterioration degree determination unit, and the control unit may increase the drive current to the motor based on the collapse current value corrected by the collapse current value correction unit.

[0012] In another aspect, the device may further include a temperature detection unit that detects the temperature of the sealing member, and the deterioration degree determination unit may integrate the temperature of the sealing member detected by the temperature detection unit at predetermined time intervals as deterioration over time, and the collapse current value correction unit may calculate a correction coefficient from the integrated value integrated by the deterioration degree determination unit based on a predetermined relationship between the integrated value and the correction coefficient, and correct the collapse current value using the correction coefficient.

[0013] In another aspect, the valve device may be provided at the entrance or exit of a chamber that is depressurized by the vacuum pump, and may further include a pressure detection unit that detects the pressure inside the chamber, and the control unit may drive the butterfly valve to the fully closed position, and then gradually increase the drive current to the motor until the pressure inside the chamber is depressurized by the vacuum pump and the pressure detected by the pressure detection unit drops to a predetermined specified pressure.

[0014] In another embodiment, the seal member may be provided around the entire periphery of the butterfly valve.

[0015] In another embodiment, the seal member may be provided over the entire inner circumferential surface of the valve hole. [Effects of the Invention]

[0016] According to the butterfly valve device system of the present invention, it is possible to suppress an increase in manufacturing costs, and to achieve high reliability by reliably maintaining airtightness when fully closed. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a system configuration diagram showing a DAC to which a butterfly valve device system according to an embodiment is applied. FIG. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. [Figure 5] 5 is a cross-sectional view corresponding to FIG. 4, showing the butterfly valve when rotated from a fully open position to a fully closed position. [Figure 6] 5 is an enlarged cross-sectional view of FIG. 4 showing the butterfly valve in a controlled fully closed position and a collapsed fully closed position. [Figure 7] 4 is a flowchart showing a full-close control routine executed by a controller of the first embodiment. [Figure 8] 4 is a time chart showing a control state of a drive current supplied to a motor in the first embodiment. [Figure 9] 10 is a flowchart showing a full-close control routine executed by a controller of a second embodiment. [Figure 10] 10 is a time chart showing a control state of a drive current supplied to a motor in a second embodiment. [Figure 11] 10 is a flowchart showing a full-close control routine executed by a controller of a third embodiment. [Figure 12] 10 is a time chart showing a control state of a drive current supplied to a motor in the third embodiment. [Figure 13] 10 is a flowchart showing a collapse current value correction routine executed by a controller of a fourth embodiment. [Figure 14] 10 is a flowchart showing a full-close control routine executed by a controller of a fifth embodiment. [Figure 15] 10 is a time chart showing a control state of a drive current supplied to a motor in a fifth embodiment. [Figure 16] 7 is an enlarged cross-sectional view corresponding to FIG. 6, showing another example in which a seal member is provided on the inner circumferential surface of a valve hole. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] The following describes one embodiment of the present invention, in which the present invention is embodied in a butterfly valve device system for DAC (Direct Air Capture). DAC is a device that separates and captures CO2 from the atmosphere, and the valve device functions to connect or disconnect the inlet and outlet of a vacuum chamber by opening or closing the butterfly valve element.

[0019] FIG. 1 is a system configuration diagram of a DAC, and first, the schematic configuration of the DAC will be explained based on this diagram. A CO2 filter 3 is disposed within the chamber 2 of the DAC 1. This CO2 filter 3 is made by supporting amine as a CO2 adsorbent on a carrier made of, for example, silica or zeolite. Therefore, the CO2 filter 3 has the property of adsorbing CO2 in the atmosphere under atmospheric pressure and room temperature, and desorbing the adsorbed CO2 under reduced pressure and high temperature.

[0020] The chamber 2 has two holes 2a and 2b, one on either side of the CO2 filter 3. As described below, air is introduced into the chamber 2 through one hole 2a and discharged through the other hole 2b after passing through the CO2 filter 3. Therefore, one hole is referred to as the inlet 2a and the other hole as the outlet 2b, and upstream and downstream are defined according to the direction of air flow. An upstream valve device 4a is provided at the inlet 2a, and a downstream valve device 4b is provided at the outlet. The inlet 2a and outlet 2b are connected or disconnected depending on the opening and closing of the valve devices 4a and 4b. The inlet 2a and outlet 2b correspond to the "inlet and outlet" in this invention.

[0021] The inlet 2a of the chamber 2 is flared, and an electric fan 5 is disposed opposite it. When the electric fan 5 operates while the upstream and downstream valve devices 4a, 4b are open, the outside air flows into the chamber 2 through the inlet 2a, passes through the inside of the CO2 filter 3, and is then discharged to the outside through the outlet 2b.

[0022] The temperature of the CO2 filter 3 is adjusted by cold water and hot water supplied via a water passage 6 attached to the chamber 2. Specifically, the water passage 6 comprises a cold inlet passage 6a through which cold water flows in from a cold water supply source (not shown), a hot inlet passage 6b through which hot water flows in from a hot water supply source (not shown), and a temperature-controlled water passage 6c through which cold water and hot water flow through the CO2 filter 3. Outside the chamber 2, the cold inlet passage 6a and the hot inlet passage 6b are respectively equipped with on-off valves 7a and 7b, and these inlet passages 6a and 6b merge and are connected to one end of the temperature-controlled water passage 6c. The temperature-controlled water passage 6c is drawn into the chamber 2 and is provided so as to intertwine inside the CO2 filter 3, and its other end is drawn out of the chamber 2 and fitted with a water pump 8.

[0023] One end of a vacuum passage 9 is connected to a location downstream of the CO2 filter 3 inside the chamber 2, and an on-off valve 10 and a vacuum pump 11 are installed in the vacuum passage 9. When the vacuum pump 11 operates while the on-off valve 10 is open, the air inside the chamber is discharged to the outside via the vacuum passage 9, and if the upstream and downstream valve devices 4a, 4 are both closed at this time, the pressure inside the chamber 2 is reduced.

[0024] The process of separating and capturing CO2 from the atmosphere by the DAC1 is controlled by a controller 13. Various sensors are connected to the input side of the controller 13, such as a pressure sensor 14 that detects the pressure P inside the chamber 2 and aperture sensors 15a, 15b that detect the aperture θ of the upstream and downstream valve devices 4a, 4b, and detection information such as the chamber pressure P from the pressure sensor 14 and the aperture θ from each aperture sensor 15a, 15b is input to the controller 13. The pressure sensor 14 corresponds to the "pressure detection unit" of the present invention, and the aperture sensors 15a, 15b correspond to the "aperture detection unit" of the present invention.

[0025] Additionally, various devices such as upstream and downstream valve devices 4a, 4b, electric fan 5, on-off valves 7a, 7b, 10, water pump 8, and vacuum pump 11 are connected to the output side of the controller 13, and each is driven by the controller 13. For example, the controller calculates a target opening tgtθ for each valve device 4a, 4b according to the progress of the CO2 separation and capture process, and controls the opening θ of each valve device 4a, 4b by supplying a drive current to the motor of the valve device 4a, 4b using, for example, well-known PID control, based on the deviation between the target opening tgtθ and the actual opening θ detected by each opening sensor 15a, 15b.

[0026] Next, we will discuss the separation and recovery of CO2 from the atmosphere, but as the details are well known, we will only provide a brief explanation. The separation and recovery process is carried out in the order of an adsorption step and a desorption step under the control of the controller 13 .

[0027] During the adsorption process, the on-off valve 10 is closed, the vacuum pump 11 is stopped, and the decompression effect does not affect the chamber 2. The on-off valve 7a is open, the on-off valve 7b is closed, the water pump 8 is operating, and cold water flows through the temperature-controlled water passage 6c as shown by arrow A in FIG. 1, maintaining the CO2 filter 3 at room temperature. The upstream and downstream valve devices 4a and 4b are open, maintaining the interior of the chamber 2 at atmospheric pressure. The electric fan 5 is then operated, and the outside air flows through the inside of the CO2 filter 3 as shown by arrow B in FIG. 1, and the CO2 contained in the air is adsorbed by the CO2 filter 3 in an environment of atmospheric pressure and room temperature.

[0028] This adsorption process continues for an adsorption time, for example, determined in a prior test, after which the process transitions to the desorption process. At this time, the electric fan 5 stops, and the upstream and downstream valve devices 4a and 4b close, isolating the chamber 2 from the outside. Furthermore, while the water pump 8 continues to operate, the on-off valves 7a and 7b reverse their open and closed states. This causes hot water to flow through the temperature-controlled water passage 6c, as indicated by arrow C in FIG. 1, and the CO2 filter 3 is heated by the heat. The on-off valve 10 then opens, and the vacuum pump 11 begins operating. The air in the chamber 2 is exhausted to the outside, as indicated by arrow D in FIG. 1, thereby reducing the pressure inside the chamber 2. The CO2 is desorbed from the CO2 filter 3, which is placed in a reduced-pressure, high-temperature environment, and is collected, for example, in a collection tank (not shown) connected to the vacuum passage 9.

[0029] The upstream and downstream valve devices 4a and 4b used in the CO2 separation and capture process described above are required to have the following performance. First, in order to efficiently adsorb CO2 in the atmosphere onto the CO2 filter 3 in the adsorption process, it is necessary to circulate a large amount of air through the CO2 filter 3. To achieve this, a butterfly-type valve device that can ensure a sufficient opening area when the valve is open is desirable.

[0030] Furthermore, the adsorption process tends to take longer than the desorption process due to the adsorption / desorption characteristics of the CO2 filter 3. Because the upstream and downstream valve devices 4a, 4b are kept open during the adsorption process, so-called normally open type valve devices that are kept open when not energized are desirable in order to reduce power consumption during this process.

[0031] In addition, if the chamber 2 is not completely isolated from the outside during the desorption process, the vacuum pump 11 will not reduce the pressure, preventing efficient desorption of CO2. Therefore, the upstream and downstream valve devices 4a, 4b are required to have the ability to reliably maintain airtightness when fully closed so that the inlet 2a and outlet 2b of the chamber 2 can be completely blocked during the desorption process.

[0032] The technology of Patent Document 1 was also devised based on the above-mentioned viewpoint, but since it required a complex structure such as a cam mechanism to move the butterfly valve element in a straight line, problems arose in terms of rising manufacturing costs and reliability of operation.

[0033] In consideration of the drawbacks of Patent Document 1, the valve device system of the present invention, which includes valve devices 4a and 4b, is designed to reliably maintain airtightness by applying a current greater than the control fully closed current corresponding to the fully closed position to the butterfly valve when it is in the fully closed position, thereby pressing the butterfly valve against the valve seat, and the details of this system are described below.

[0034] Fig. 2 is a perspective view showing the valve devices 4a and 4b, Fig. 3 is a front view showing the valve devices 4a and 4b, Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3, and Fig. 5 is a cross-sectional view corresponding to Fig. 4 showing the butterfly valve when rotated from the fully open position to the fully closed position. The upstream valve device 4a will be described below, but the downstream valve device 4b has the same configuration.

[0035] The upstream valve device 4a comprises a valve body 21 equipped with a butterfly valve 26, and a mechanism 22 that opens and closes the butterfly valve 26. The mechanism 22 corresponds to the "drive mechanism" of the present invention.

[0036] A valve hole 23 having a circular cross section is formed through the valve body 21, and a flange portion 24 is formed at one open end of the valve hole 23, and a valve seat 23a is formed within the valve hole 23, the diameter of which tapers toward the flange portion 24. When assembled to the DAC1, the flange portion 24 of the upstream valve device 4a is fastened to the inlet 2a or outlet 2b of the chamber 2 with bolts (not shown).

[0037] A valve stem 25 is disposed in the valve body 21 so as to pass through the valve hole 23, and both ends of the valve stem 25 are rotatably supported by the valve body 21. Within the valve hole 23, a disk-shaped butterfly valve 26 is fixed to the valve stem 25 with screws (not shown). As will be described in detail below, the butterfly valve 26 is driven by the mechanism 22 to rotate about the valve stem 25 between the fully open position shown in Figure 4 and the fully closed position shown by the solid line in Figure 5. A seal groove 26a is formed around the entire periphery of the butterfly valve 26, and an annular seal member 27 made of rubber or the like is fitted into the seal groove 26a. When the butterfly valve 26 is in the fully closed position, the seal member 27 elastically abuts against the valve seat 23a of the valve hole 23 to maintain an airtight seal. The valve body 21, the valve stem 25, and the butterfly valve 26 are made of corrosion-resistant and heat-resistant stainless steel or the like.

[0038] One end of the valve shaft 25 (the left end in FIG. 3) protrudes from the valve body 21, and the mechanism unit 22 is connected to the portion of the valve body 21 corresponding to this protruding end. As shown by the dashed line in FIG. 3, the mechanism unit 22 rotatably supports a transmission shaft 28 coaxially with the valve shaft 25, and the transmission shaft 28 and the valve shaft 25 rotate together while their relative rotation is restricted via interlocking fittings 29a and 29b that engage with each other. A motor 30 is attached to the underside of the mechanism unit 22, and the rotation of the motor 30 is transmitted to the transmission shaft 28 via a gear train (not shown). The mechanism unit 22 is provided with a connector 32, and when the valve devices 4a and 4b (not shown) are assembled to the DAC1, a harness extending from the controller 13 is connected to the connector 32 to supply a drive current to the motor 30.

[0039] A return spring 31 is wound around the protruding side of the valve stem 25, and in order to cause the upstream valve device 4a to function as a normally open type, the return spring 31 biases the valve stem 25 clockwise in Figure 5, i.e., toward the opening side of the butterfly valve 26. Rotation of the valve stem 25 toward the opening side is restricted via the transmission shaft 28 by a stopper (not shown) provided in the mechanism unit 22, and at this time the butterfly valve 26 is maintained in the fully open position indicated by the two-dot chain line in Figure 5. The return spring 31 corresponds to the "biasing member" of the present invention.

[0040] 5, the butterfly valve 26 is closed. In the fully closed position, the seal member 27 on the periphery of the butterfly valve 26 abuts against the valve seat 23a in the valve hole 23, maintaining airtightness between the upstream and downstream sides of the butterfly valve 26. As the butterfly valve 26 transitions from the fully open position to the fully closed position, the drive current supplied to the motor 30 is gradually increased based on PID control or the like to increase the drive force of the motor 30 against the gradually increasing force of the return spring 31.

[0041] The state in which airtightness is maintained by the butterfly valve 26 at this time will be described in further detail with reference to FIG. As shown by the solid line in Figure 6, the valve hole 23 is kept airtight when the seal member 27 abuts against the valve seat 23a. If the driving force of the motor 30 is further increased, as shown by the two-dot chain line, the butterfly valve 26 slightly changes its position toward the closing side around the valve stem 25, crushing the elastic seal member 27 (denoted by crushing amount = A). As a result, the seal member 27 is pressed even more firmly against the valve seat 23a by its own elastic force, more reliably maintaining the airtightness of the valve hole 23. In the following explanation, the position of the butterfly valve 26 when the seal member 27 abuts against the valve seat 23a will be referred to as the controlled fully closed position, and the position of the butterfly valve 26 when the seal member 27 is crushed will be referred to as the crushed fully closed position.

[0042] Next, the control of the DAC 1 executed by the controller 13 will be described below as first to fifth embodiments. [First embodiment] FIG. 7 is a flowchart showing a full-close control routine executed by the controller 13 of the first embodiment, and FIG. 8 is a time chart showing the control state of the drive current supplied to the motor 30 of the first embodiment. When the CO2 separation and capture process transitions from the adsorption process to the desorption process, the routine of FIG. 7 is executed at predetermined control intervals to close each of the valve devices 4a, 4b. Note that there are slight individual differences between the upstream and downstream valve devices 4a, 4b, and the controlled full-open positions, etc. also differ accordingly, so the routine of FIG. 7 is executed individually for each of the valve devices 4a, 4b. The controller 13 when executing the routine of FIG. 7 corresponds to the "control unit" of the present invention.

[0043] When the valve closing operation of the valve devices 4a, 4b is initiated in step S1 in Figure 7, the supply of drive current to the motor 30 is initiated in step S2 to drive the butterfly valve 26 to the closing side. Therefore, as shown in Figure 8, the drive current to the motor 30 begins to increase from 0 as the valve closing operation begins (point a in Figure 8). In the following step S3, it is determined whether the butterfly valve 26 has reached the controlled fully closed position. At the controlled fully closed position, as shown by the solid line in Figure 6, the seal member 27 of the butterfly valve 26 abuts against the valve seat 23a of the valve hole 23, and the sliding resistance acts in a direction that prevents the butterfly valve 26 from changing its position. Therefore, when the control start position is reached, the drive current to the motor 30 increases in a small stepwise manner, and the determination in step S3 is made based on this change in current.

[0044] If the determination in step S3 is No (negative), the process returns to step S2, and the processing in step S2 continues. As the biasing force of return spring 31 gradually increases with driving toward the closing side, the drive current supplied to motor 30 based on PID control or the like is gradually increased, as shown in Figure 8, and at some point, it reaches current value C1 corresponding to the controlled fully closed position (point b in Figure 8). If the determination in step S3 is Yes (affirmative) based on a slight increase in drive current, the process proceeds to step S4, where the drive current to motor 30 is increased in a stepped manner to a preset collapse current value C2, and then the routine ends.

[0045] The collapse current value C2 is set based on a prior test as a current value higher than the current value C1 corresponding to the controlled fully closed position in order to achieve a collapse amount A of the seal member 27, shown by the two-dot chain line in Fig. 6, which is suitable for maintaining airtightness of the valve orifice 23. Therefore, as shown in Fig. 8, the drive current to the motor 30 increases in a stepped manner from the current value C1 to the collapse current value C2 (point c in Fig. 8), and is thereafter maintained at the collapse current value C2. As a result, the butterfly valve 26 is maintained in a position in which the seal member 27, shown by the two-dot chain line in Fig. 6, is collapsed, thereby reliably maintaining airtightness of the valve orifice 23.

[0046] In this way, the upstream and downstream valve devices 4a, 4b are held closed when the desorption process of DAC1 begins, and when the adsorption process begins after the desorption process is completed, the valve devices 4a, 4b are opened. At this time, as in the drive control of a general valve device, the drive current to the motor 30 is controlled to gradually decrease, and the force of the return spring 31 drives the butterfly valve 26 in the valve opening direction.

[0047] Next, the effects of the valve device system of this embodiment will be described. In the drive control of a typical valve device system, when the butterfly valve reaches its controlled fully closed position, the current value at that time is maintained to keep the butterfly valve in the controlled fully closed position. In contrast, in this embodiment, when the butterfly valve 26 reaches its controlled fully closed position, the drive current is increased in a stepped manner to a higher crushing current value C2. As a result, as shown by the two-dot chain line in Figure 6, the seal member 27 is crushed and pressed more firmly against the valve seat 23a, thereby more reliably maintaining the valve hole 23 airtight.

[0048] Furthermore, the structural requirements required for the upstream and downstream valve devices 4a, 4b to achieve these effects do not require complex structures such as cam mechanisms as in the valve device of Patent Document 1. Furthermore, the routine shown in Figure 7 executed by the controller 13 can be easily implemented by modifying the control program, so there is almost no increase in costs. Therefore, the valve device system of this embodiment can suppress increases in manufacturing costs and achieve high reliability by reliably maintaining airtightness when fully closed.

[0049] [Second embodiment] Next, a second embodiment will be described, but the structure of the valve devices 4a and 4b is the same as that of the first embodiment, and the difference lies in the control content of the controller 13, so the description will focus on the difference. This also applies to the second to fifth embodiments.

[0050] Fig. 9 is a flowchart showing a full-close control routine executed by the controller 13 of the second embodiment, and Fig. 10 is a time chart showing the control state of the drive current supplied to the motor 30 of the second embodiment. In Fig. 9, the same step numbers are assigned to the processes that are the same as those in Fig. 7.

[0051] 9, the valve closing operation of the valve devices 4a, 4b is initiated in step S1, the butterfly valve 26 is driven to the closing side in step S2, and when the butterfly valve 26 reaches the control fully closed position in step S3, the drive current to the motor 30 at that time is stored as a control fully closed current value C1 in step S11. In the following step S4, the drive current to the motor 30 is increased in a stepped manner to a zero current value C2, and then in step S12 it is determined whether a preset waiting time t1 has elapsed. If the determination is No, the process returns to step S4, and the processing of step S4 continues.

[0052] The standby time t1 is set based on a prior test as the time required for the supply of the collapse current value C2 to be reflected in the desired collapse allowance A of the seal member 27. If the determination in step S12 is Yes, the routine proceeds to step S13, where the drive current to the motor 30 is reduced in a stepped manner to the control fully-closed current value C1 stored in step S11, and then the routine ends. Therefore, as shown in Fig. 10, the drive current to the motor 30 is maintained at the collapse current value C2 for the standby time t1 (point d in Fig. 10), then reduced in a stepped manner to the control fully-closed current value C1 (point e in Fig. 10), and thereafter maintained at the control fully-closed current value C1.

[0053] Although a redundant description will not be given, the present embodiment also provides the same effects as the first embodiment. The process in step S13 is based on the following findings.

[0054] When the seal member 27 is held in the collapsed fully closed position indicated by the two-dot chain line in Figure 6, its own elasticity presses it against the valve seat 23a. The frictional resistance generated between the seal member 27 and the valve seat 23a at this time acts in a direction that prevents the butterfly valve 26 from changing its position toward the open side due to the biasing force of the return spring 31. Although the magnitude of the frictional resistance varies depending on various conditions, such as the material of the seal member 27 (related to its elasticity and friction coefficient) or the contact angle of the seal member 27, which follows an arc-shaped path, with the valve seat 23a, the butterfly valve 26 may be held in the collapsed fully closed position even if the drive current to the motor 30 is reduced. Anticipating such a case, in this embodiment, the drive current is reduced to the control fully closed current value C1, and the drive current to the motor 30 can be reduced to the control fully closed current value C1, which is lower than the collapse current value C2, until the end of the desorption process. Therefore, compared to the first embodiment, the effect of reducing the power consumption of the motor 30, and therefore the cost for carrying out the CO2 separation and capture process, can be obtained.

[0055] Furthermore, the control fully closed current value C1 is the minimum drive current required to maintain the butterfly valve 26 in the control fully closed position, and is an accurate value that is not affected by the individual differences between the valve devices 4a, 4b when the valve devices 4a, 4b are actually set to the control fully closed position, as stored in step S11. By reducing the drive current to this control fully closed current value C1, the maximum power saving effect can be achieved. However, it is not necessary to reduce the drive current to the control fully closed current value C1, and instead of the control fully closed current value C1, it may be reduced to any current value set, for example, between the collapse current value C2 and the control fully closed current value C1.

[0056] [Third embodiment] Next, a third embodiment will be described. FIG. 11 is a flowchart showing a full-close control routine executed by the controller 13 of the third embodiment, and FIG. 12 is a time chart showing the control state of the drive current supplied to the motor 30 of the third embodiment.

[0057] The processing of steps S1 to S3, 11, 4, 12, and 13 in FIG. 11 is the same as in the second embodiment, and then in step S21, it is determined whether a preset waiting time t2 has elapsed. If the determination is No, the process returns to step S13, and the processing of step S13 continues. As the drive current to the motor 30 decreases, the biasing force of the return spring 31 may release the frictional resistance between the seal member 27 and the valve seat 23a, causing the butterfly valve 26 to return from the collapsed fully closed position to the controlled fully closed position, and this possibility increases with the passage of time. The waiting time t2 is set based on a prior test as the time that elapses before such a phenomenon occurs.

[0058] When the determination in step S21 is Yes, the process proceeds to step S22, where the drive current to the motor 30 is gradually increased step by step to the crushing current value C2. Then, in the subsequent step S23, it is determined whether or not the preset waiting time t3 has elapsed. When the determination is No, the process returns to step S22, so the processing of step S22 continues. Even if the frictional resistance between the seal member 27 and the valve seat 23a is on the verge of being released by the biasing force of the return spring 31, the frictional resistance is restored because the drive current to the motor 30 increases, and the butterfly valve 26 continues to be kept in the fully closed position by crushing.

[0059] The waiting time t3 is set based on a prior test as the supply time of the crushing current value capable of restoring such frictional resistance. Thus, since the waiting time t3 is for the purpose of restoring the frictional resistance, in this embodiment, it is set to be shorter (t3 < t1) than the waiting time t1, but it is not limited to this. For example, it may be set to the same value as the waiting time t1. Also, in step S22, instead of the crushing current value C2, for example, a current value C3 (C1 < C3 < C2) that is higher than the fully closed control current value C1 and lower than the crushing current value C2 may be used.

[0060] When the determination in step S23 is Yes, the process returns to step S13, and thereafter, the processing of steps S13, 21 to 23 is repeated. Therefore, as shown in FIG. 12, the drive current to the motor 30 is in a control state (point e - f in FIG. 12) where it is maintained at the fully closed control current value C1 for the waiting time t2 after decreasing from the crushing current value C2 to the fully closed control current value C1, and a control state (point g - h in FIG. 12) where it is maintained at the crushing current value C2 for the waiting time t3, which are alternately repeated.

[0061] In this embodiment as well, although redundant explanations are not given, the same effects as those of the first and second embodiments can be obtained. In addition, after the butterfly valve 26 is collapsed to the fully closed position as described above, the drive current to the motor 30 is alternately switched between the control fully closed current value C1 and the collapse current value C2. This makes it possible to reduce the power consumption of the motor 30 more than in the first embodiment, and to more reliably maintain the butterfly valve 26 in the collapsed fully closed position than in the second embodiment.

[0062] [Fourth embodiment] Next, a fourth embodiment will be described. This embodiment focuses on the phenomenon that when the seal member 27 of the butterfly valve 26 hardens due to aging, it becomes difficult to collapse, and as a result, it becomes difficult to collapse the butterfly valve 26 and rotate it to the fully closed position. This measure can be applied to any of the first to third embodiments, but as an example, an application of this measure to the first embodiment will be described below.

[0063] In simple terms, the countermeasure of this embodiment is to correct the collapse current value C2 to the upward side in accordance with the deterioration of the seal member 27 over time, and uses the temperature history to which the seal member 27 has been exposed up to now as an index for estimating the deterioration over time. For this purpose, the valve gear system of this embodiment is provided with a temperature sensor 41 as shown in FIG. 3, and the temperature inside the valve hole 23 detected by this temperature sensor 41 is input to the controller 13. Because the temperature inside the valve hole 23 correlates with the temperature of the seal member 27, it will hereinafter be referred to as the seal temperature T. The temperature sensor 41 corresponds to the "temperature detection unit" of this invention.

[0064] When the seal temperature T is detected at predetermined time intervals and sequentially integrated, the integrated value increases as the temperature of the environment in which the seal member 27 is used increases and as the duration of use increases. Therefore, the integrated temperature can be considered to correlate with the temperature history of the seal member 27 and, ultimately, the degree of deterioration over time. For this reason, the controller 13 stores a control map that defines the relationship between the integrated value of the seal temperature T and a correction coefficient k (>1.0) for correcting the collapse current value C2, and also stores the collapse current value C2 used in the first embodiment as an initial value. The control map calculates a larger correction coefficient k as the integrated value of the seal temperature T increases.

[0065] FIG. 13 is a flowchart showing a collapse current value correction routine executed by the controller 13 of the fourth embodiment, and the controller 13 executes this routine in parallel with the routine of FIG. First, in step S31, the sealing temperature T is read, and in step S32, the current sealing temperature T is added to the cumulative value of the sealing temperature T up to now. In the following step S33, a correction coefficient k is calculated from the cumulative value of the sealing temperature T based on the control map. Then, in step S34, the initial value of the collapse current value C2 is multiplied by the correction coefficient k to calculate the current collapse current value C2. In step S35, it is determined whether a preset sampling time t4 has elapsed. If the determination is Yes, the process returns to step S31. In this way, the collapse current value C2 is successively updated to a value corresponding to the temperature history of the sealing member 27 and, ultimately, to deterioration over time, and the latest collapse current value C2 is applied to the process of step S4 in FIG. 7.

[0066] The controller 13 when executing the processes of steps S31 and S32 corresponds to the "deterioration degree determination unit" of the present invention, and the controller 13 when executing the processes of steps S33 and S34 corresponds to the "crushing current value correction unit" of the present invention.

[0067] 8 also shows an example of the collapse current value C2 when the seal member 27 has deteriorated over time, with the dashed line indicating that the collapse current value C2 gradually increases from the initial value indicated by the solid line in accordance with the deterioration of the seal member 27. Therefore, even if the seal member 27 has hardened due to deterioration over time, the butterfly valve 26 can be rotated to the collapsed fully closed position. As a result, this embodiment achieves the effect of enabling the butterfly valve 26 to reliably maintain the valve hole 23 airtight, without being affected by the deterioration of the seal member 27 over time.

[0068] Note that the present invention may be embodied in the second or third embodiment instead of the first embodiment. In the second embodiment, the collapse current value C2 obtained by the process of Fig. 13 is applied to step S4 of Fig. 9, and in the third embodiment, the collapse current value C2 is applied to steps S4 and S22 of Fig. 11. The time charts of Fig. 10 and Fig. 12 also show, with dashed lines, examples of the collapse current value C2 when the seal member 27 has deteriorated over time. Furthermore, although the temperature history is used as an index for estimating the deterioration of the seal member 27 over time, the usage time of the seal member 27 may be used instead, for example.

[0069] [Fifth embodiment] Next, a fifth embodiment will be described. This embodiment focuses on the same phenomenon as the fourth embodiment, but employs a different countermeasure method.

[0070] Fig. 14 is a flowchart showing a full-close control routine executed by the controller 13 of the fifth embodiment, and Fig. 15 is a time chart showing the control state of the drive current supplied to the motor 30 of the fifth embodiment. Note that in this embodiment, it is assumed that the vacuum pump 11 starts to reduce the pressure inside the chamber 2 at the same time as the valve devices 4a, 4b start to close the valves.

[0071] 14, the valve closing operation of the valve devices 4a, 4b is initiated in step S1, the butterfly valve 26 is driven to the closing side in step S2, and when the butterfly valve 26 reaches the controlled fully closed position in step S3, the process proceeds to step S41. In step S41, the chamber pressure P detected by the pressure sensor 14 is read, and in the following step S42, it is determined whether the chamber pressure P is equal to or less than a specified pressure P0 that is preset as a value suitable for CO2 desorption. If the determination is No, the process proceeds to step S43, where a preset correction amount is added to the drive current to the motor 30 for an increase correction, and then the process returns to step S41. Note that immediately after the butterfly valve 26 reaches the controlled fully open position, a correction amount is added to the drive current corresponding to the controlled fully closed current value C1 in step S43.

[0072] In this way, the processes of steps S41 to S43 are repeated, and the chamber pressure P gradually decreases and the drive current to the motor 30 gradually increases. Then, when the condition of step S42 is satisfied, the process proceeds to step S44, and the drive current at that time is maintained.

[0073] Therefore, as shown in FIG. 15, when the drive current to the motor 30 reaches the control fully closed current value C1 (point b in FIG. 15), the process of step S43 gradually increases the drive current to the motor 30. Then, when the chamber pressure P drops to the specified pressure P0, the increase correction of the drive current is stopped and the drive current is maintained at the value at that time (point c in FIG. 15). The specified pressure P0 is a pressure suitable for CO2 desorption, and a state in which this pressure is maintained can be considered as the butterfly valve 26 being maintained in the collapsed fully closed position shown by the two-dot chain line in FIG. 6. In other words, the drive current to the motor 30 is controlled to an appropriate value corresponding to the collapse current value C2 described in the first to third embodiments. Therefore, the seal member 27 is collapsed and pressed more strongly against the valve seat 23a, thereby more reliably maintaining the valve hole 23 airtight.

[0074] Furthermore, if the seal member 27 of the butterfly valve 26 hardens due to deterioration over time, the timing at which the condition in step S42 is satisfied will be delayed, and the increase correction executed in step S43 during that time will naturally increase the drive current to the motor 30. Therefore, similar to the fourth embodiment, the valve hole 23 can be reliably maintained airtight without being affected by deterioration of the seal member 27 over time.

[0075] The aspects of the present invention are not limited to these embodiments. For example, in the above-described embodiments, the butterfly valve device system for DAC is embodied, but the application is not limited to this, and the present invention may be applied to a valve device system used in a semiconductor manufacturing process, such as that described in Patent Document 1.

[0076] Furthermore, while the above-described embodiments provide a seal member 27 around the butterfly valve 26, a seal member may be provided on the inner circumferential surface of the valve hole 23, as described in, for example, Patent Document 1. Another example is shown in FIG. 16 , in which a circumferentially extending seal groove 51 is formed around the entire inner circumferential surface of the valve hole 23, and a rubber annular seal member 52 is fitted into this seal groove 51 as a valve seat. When the butterfly valve 26 is in the fully closed position, as shown by the solid line, its entire periphery abuts against the inner circumferential surface of the seal member 52, maintaining airtightness of the valve hole 23. When the driving force of the motor 30 is increased, the butterfly valve 26 slightly changes its position around the valve stem 25 toward the closed side, compressing the seal member 52 (deformation amount = A), as shown by the two-dot chain line. Therefore, even in this case, the elasticity of the seal member 52 more reliably maintains airtightness of the valve hole 23, achieving the same effects as the above-described embodiments. [Explanation of symbols]

[0077] 2 chambers 2a Entrance (doorway) Exit 2b (entrance / exit) 4a Upstream valve device 4b Downstream valve device 11 Vacuum pump 13 Controller (control unit, deterioration degree determination unit, collapse current value correction unit) 14 Pressure sensor (pressure detection part) 15a Opening sensor (opening detection section) 15b Opening sensor (opening detection unit) 22 Mechanism (drive mechanism) 23 Valve orifice 25 Valve stem 26 Butterfly valve 27,52 Sealing member 30 motor 31 Return spring (biasing member) 41 Temperature sensor (temperature detection part)

Claims

1. a butterfly valve supported by a valve stem in a valve hole so as to be able to open and close, biased to the opening side by a biasing member, and having a periphery that abuts against the inner peripheral surface of the valve hole via an elastic seal member in a fully closed position; a drive mechanism connected to the valve shaft and configured to rotate the valve shaft by a driving force of a motor; an opening detection unit that detects the opening of the butterfly valve; a control unit that supplies a drive current to the motor, drives the butterfly valve to the closing side against the biasing member in response to an increase in the drive current, and controls the opening of the butterfly valve based on the opening detected by the opening detection unit and a target opening; Equipped with When the butterfly valve is driven to the fully closed position, the control unit increases the drive current to the motor to a crushing current value that is higher than a control fully closed current value required to drive the butterfly valve to the fully closed position. A butterfly valve device system comprising:

2. The control unit increases the drive current to the motor from the control fully closed current value to the collapse current value, and then maintains the drive current at the collapse current value.

2. The butterfly valve device system according to claim 1 .

3. The control unit increases the drive current to the motor from the control fully closed current value to the collapse current value, and then decreases the drive current to the control fully closed current value.

2. The butterfly valve device system according to claim 1 .

4. The control unit increases the drive current to the motor from the control fully closed current value to the collapse current value, and then alternately switches between the control fully closed current value and the collapse current value.

2. The butterfly valve device system according to claim 1 .

5. a deterioration degree determination unit that determines deterioration of the sealing member over time; a damping current value correcting unit that corrects the damping current value based on the aging deterioration determined by the deterioration degree determining unit; Furthermore, The control unit increases the drive current to the motor based on the collapse current value corrected by the collapse current value correction unit.

3. The butterfly valve device system according to claim 1 or 2.

6. a temperature detector for detecting the temperature of the sealing member; the deterioration degree determining unit integrates the temperature of the sealing member detected by the temperature detecting unit at predetermined time intervals as the aging deterioration; The crash current value correction unit calculates a correction coefficient from the integrated value calculated by the deterioration degree determination unit based on a predetermined relationship between the integrated value and a correction coefficient, and corrects the crash current value using the correction coefficient.

6. The butterfly valve device system according to claim 5.

7. the valve device is provided at an inlet / outlet of a chamber that is decompressed by a vacuum pump; a pressure detection unit that detects the pressure inside the chamber; The control unit drives the butterfly valve to a fully closed position, and then gradually increases the drive current to the motor until the pressure inside the chamber is reduced by the vacuum pump and the pressure detected by the pressure detection unit decreases to a predetermined specified pressure.

2. The butterfly valve device system according to claim 1 .

8. The seal member is provided around the entire periphery of the butterfly valve.

2. The butterfly valve device system according to claim 1 .

9. The sealing member is provided over the entire inner circumferential surface of the valve hole.

2. The butterfly valve device system according to claim 1 .

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