JP2018045432A - Vacuum pressure control system and controller for vacuum pressure control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum pressure control system and a controller for vacuum pressure control which are compact, inexpensive and excellent in control responsiveness.SOLUTION: A vacuum pressure control system 1 collects performance characteristic data of a vacuum valve 2 at first to fourth inflection points B1-B4 where a change rate, of operation pressure of the vacuum valve 2 measured by an operation pressure sensor 3k, changes. A controller 4 generates a valve open degree control signal using the performance characteristic data and outputs the signal to an electropneumatic regulator 3. The electropneumatic regulator 3 regulates operation pressure of the vacuum valve 2 based on a valve open degree measurement signal of the operation pressure sensor 3k and the valve open degree control signal of the controller 4. Thus, the vacuum pressure control system 1 causes internal pressure of a vacuum vessel 8 to reach a vacuum pressure target value by opening/closing the vacuum valve 2 according to an instruction of the controller 4 so as to control a flow rate of a gas flowing from the vacuum vessel 8 to a vacuum pump 9.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a vacuum pressure control system and a vacuum pressure control system for controlling the internal pressure of the vacuum vessel to a vacuum pressure target value by controlling the valve opening degree of a vacuum valve installed between the vacuum vessel and the vacuum pump. Concerning the controller.

  For example, in a semiconductor manufacturing apparatus, the internal pressure of a vacuum vessel that affects product quality is controlled by a vacuum pressure control system. For example, in the vacuum pressure control system described in Patent Document 1, a vacuum valve is disposed between a vacuum vessel and a vacuum pump. In the vacuum valve, a position sensor is disposed so as to surround the shaft connected to the piston, and the displacement of the shaft, that is, the separation distance (valve opening degree) of the valve body connected to the shaft with respect to the valve seat is detected. When the vacuum pressure control circuit outputs a pressure control signal to the valve opening control circuit based on the deviation between the internal pressure of the vacuum vessel and the vacuum pressure target value, the valve opening control circuit receives an input from the pressure control signal and the position sensor. And the drive signal for controlling the valve opening is output to the supply solenoid valve and the exhaust solenoid valve. Then, the operating fluid is supplied to and exhausted from the vacuum valve by the supply solenoid valve and the exhaust solenoid valve, and the operation pressure is controlled. The valve opening degree of the vacuum valve changes according to the operation pressure, and controls the gas exhausted from the vacuum vessel to the vacuum pump. Thereby, the internal pressure of a vacuum vessel falls and it is controlled to a vacuum pressure target value.

JP 2006-195733 A

However, in the vacuum pressure proportional control system described in Patent Document 1, the valve opening is detected by a position sensor surrounded by the vacuum valve, so the vacuum valve is large and expensive.
In addition, vacuum valves have individual differences in operating characteristics due to differences in sliding resistance of packings mounted on pistons, assembly tolerances and dimensional tolerances of parts, and the like. The vacuum pressure control system described in Patent Document 1 does not individually collect the operating characteristics of the vacuum valve. Therefore, in the vacuum pressure control system described in Patent Document 1, it is necessary to control the operating pressure of the vacuum valve in consideration of individual differences in operating characteristics. In this case, the dead zone for exhausting and supplying the operating fluid was increased and the control response was poor.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a vacuum pressure control system and a vacuum pressure control controller that are small, inexpensive, and have good control response.

One embodiment of the present invention has the following configuration.
(1) An operation chamber defined by a piston, a valve body that moves integrally with the piston, a valve seat that contacts or separates from the valve body, and a seal load that seals the valve body to the valve seat. A vacuum valve disposed between a vacuum vessel and a vacuum pump, and a valve opening degree of the vacuum valve based on a deviation between an internal pressure of the vacuum vessel and a vacuum pressure target value In a vacuum pressure control system having a controller that outputs a valve opening control signal for controlling an operation pressure, an operating pressure sensor that measures an operating pressure and outputs an operating pressure measurement signal, the valve opening control signal, and the operating pressure measurement An operation pressure control mechanism for supplying and exhausting an operation fluid to and from the operation chamber based on a signal and controlling the operation pressure, and the controller has a change rate of the operation pressure based on the operation pressure measurement signal. When the inflection point to be detected is detected and the operation characteristic data collecting means for collecting the operation characteristic data of the vacuum valve is included, and the internal pressure is controlled to the vacuum pressure target value, the operation characteristic data is used to A valve opening control signal is generated and output to the operation pressure control mechanism.

  The piston of the vacuum valve stops at the valve seat side limit position when the valve body seals to the valve seat by the seal load applying means. In this case, the volume of the operation chamber does not change even when the operation fluid is exhausted, and the operation pressure rapidly decreases. Further, the piston moves to the counter valve seat side limit position and stops to maximize the valve opening. In this case, the volume of the operation chamber does not change even when the operation fluid is supplied, and the operation pressure increases rapidly. On the other hand, the piston moves in proportion to the operating pressure between the valve seat side limit position and the counter valve seat side limit position. In this case, since the volume of the operation chamber varies according to the supply / exhaust of the operation pressure, the operation pressure changes gradually. Therefore, the operating pressure is such that the valve body starts to move in the counter valve seat direction from the fully closed position, the fully open point where the valve body reaches the fully open position, and the valve body starts to move in the valve seat direction from the fully open position. The rate of change changes at the valve closing start point and the fully closed point where the valve body seals to the valve seat. The operating pressure at these inflection points is the operating pressure at the end of valve opening, the end at the end of valve opening, the end at the start of valve closing, and the end at the end of valve closing in the hysteresis characteristics of the vacuum valve. Respectively. Therefore, the operation characteristic data of the vacuum valve can be collected by detecting the inflection point of the operating pressure.

  According to the above configuration, the vacuum pressure control system collects the operating characteristic data of the vacuum valve from the inflection point where the operating pressure of the vacuum valve measured by the operating pressure sensor changes the rate of change, and uses it to control the controller Generates a valve opening control signal and outputs it to the operating pressure control mechanism. The operation pressure control mechanism controls the operation pressure of the vacuum valve based on the operation pressure measurement signal of the operation pressure sensor and the valve opening control signal of the controller. As a result, the vacuum pressure control system opens and closes the vacuum valve in accordance with instructions from the controller, and controls the flow rate of the gas flowing from the vacuum container to the vacuum pump, whereby the internal pressure of the vacuum container reaches the vacuum pressure target value. Such a vacuum pressure control system controls the opening degree of the vacuum valve by grasping the operation of the vacuum valve from the inflection point of the operation pressure measured by the operation pressure sensor without providing a position sensor in the vacuum valve. The system can be made small and inexpensive. In addition, the vacuum pressure control system controls the valve opening of the vacuum valve using the operation characteristic data unique to the vacuum valve, so there is no dead zone where the valve opening does not change even when the operating fluid is supplied or exhausted. Responsiveness can be improved.

(2) In the configuration described in (1), the operation characteristic data collection unit changes from a small decrease rate to a large decrease within a range in which a decrease in the operation pressure is detected based on the operation pressure measurement signal. By detecting a small-large decrease inflection point and storing the operation pressure at the small-large decrease inflection point as a full-closed operation pressure parameter of a full-close point where the valve body seals the valve seat, The operation characteristic data is collected, and the controller generates the valve opening control signal so that the operation pressure matches the operation pressure parameter when fully closed when the vacuum valve is fully closed. It is preferable.

  When the operating fluid is exhausted from the operation chamber, the vacuum valve moves in the direction of the valve seat as the operating pressure decreases until the valve body seals to the valve seat. Stop. In this case, the change rate of the operating pressure changes from a small state to a large state at the time when the valve body seals to the valve seat. Therefore, in the range where the operating pressure decreases, the operating pressure at the small-large decreasing inflection point where the decreasing rate changes from a small state to a large state can be set as the operating pressure parameter for the fully closed point.

  According to the above configuration, when the operating pressure in the operating chamber reaches the fully closed operating pressure parameter, the operating fluid is no longer exhausted from the operating chamber, so that the vacuum valve is closed after the vacuum valve is closed. Do not exhaust the operation fluid from the operation chamber. Therefore, in the vacuum pressure control system, the time for making the vacuum valve fully closed and the time for making the vacuum valve open from the fully closed state are shortened, and the control response can be improved.

(3) In the configuration described in (1) or (2), the operation characteristic data collection unit detects a increase in the operation pressure based on the operation pressure measurement signal, and increases from a small increase rate state. By detecting a small-large increase inflection point that changes to a state, and storing the operation pressure at the small-large increase inflection point as a full-open operation pressure parameter of the full-open point at which the valve opening is maximized, Collecting the operating characteristic data, the controller generating the valve opening control signal so as to match the operating pressure with the operating pressure parameter when fully open when the vacuum valve is fully opened; Is preferred.

  When the operating fluid is supplied to the operation chamber, the vacuum valve moves in the counter valve seat direction as the operating pressure increases until the piston reaches the counter valve seat limit position, and reaches the counter valve seat limit position. When it reaches, it stops. In this case, when the piston reaches the limit position on the counter-valve seat side and the valve body is placed in the fully open position (when the valve opening is maximized), the increase rate of the operating pressure is small to large. To change. Therefore, within the range in which the operating pressure increases, the operating pressure at the small-large decreasing inflection point where the increasing rate changes from a small state to a large state can be set as the fully-opening operating pressure parameter.

  According to the above configuration, when the operation pressure in the operation chamber reaches the operation pressure parameter when fully opened, the operation fluid is not supplied to the operation chamber when the operation pressure in the operation chamber reaches the fully open operation pressure parameter. Do not waste the operating fluid. In such a vacuum pressure control system, the time for the vacuum valve to be fully opened and the time for the vacuum valve to be closed from the fully open state can be shortened, and the control response can be improved.

(4) In the configuration described in (3), the operation characteristic data collection unit changes from a state in which the increase rate is large to a small state in a range where the increase in the operation pressure is detected based on the operation pressure measurement signal. A large-to-small increase inflection point is detected, and the operation pressure at the large-to-small increase inflection point is stored as an operation pressure parameter at the valve start movement point of the valve start movement point at which the valve body starts to separate from the valve seat. When detecting a decrease in the operation pressure based on the operation pressure measurement signal, a large-small decrease inflection point where the decrease rate changes from a large state to a small state is detected, and the large-small decrease inflection point is detected. The operation characteristic data is collected by storing the operation pressure as the operation pressure parameter at the valve closing start point of the valve closing start point at which the valve body starts to move in the valve seat direction from the fully open position, Based on the differential pressure between the fully closed operating pressure parameter and the valve start operating pressure parameter, and the differential pressure between the fully opened operating pressure parameter and the valve closed starting pressure parameter, the bias value is automatically Automatic bias value setting means for automatically setting the bias value when the valve is opened from the fully closed state and when the vacuum valve is closed from the fully opened state Is preferably output.

  When the operation fluid is supplied to the operation chamber, the vacuum valve is stopped even if the operation pressure is supplied while the operation pressure is equal to or lower than the seal load, and when the operation pressure becomes larger than the seal load, Starts moving in the direction of the anti-valve seat. In this case, when the piston moves in the direction opposite to the valve seat and starts to separate the valve body from the valve seat (when the valve opening begins to increase), the operating pressure increase rate changes from a large state to a small state. To do. Therefore, the operation pressure at the large-to-small increase inflection point at which the increase rate changes from a large state to a small state within the range in which the operation pressure increases can be set as the operation pressure parameter for all start movements of the valve start movement point.

  In addition, when the operating fluid is exhausted from the operation chamber, the vacuum valve does not change the volume of the operation chamber while the piston stops at the counter-valve seat limit position, and the piston is moved from the counter-valve seat limit position. When it starts to move in the sitting direction, the volume of the operation chamber decreases. In this case, when the valve body starts to move in the valve seat direction from the fully open position, the operating pressure decreases from a large reduction state to a small state. Therefore, in the range where the operating pressure decreases, the operating pressure at the small-large decreasing inflection point where the decreasing rate changes from a large state to a small state can be set as the operating pressure parameter at the valve closing start point of the valve closing start point.

  According to the above configuration, the vacuum pressure control system outputs a bias value when the vacuum valve is in the fully closed state, whereby the valve body moves immediately from the fully closed position to the valve start moving position, Response time can be shortened. Further, by outputting a bias value when the vacuum valve is fully open, the valve body moves immediately from the fully open position to the valve closing start position, and the response time at the time of valve closing start can be shortened. This is because when the vacuum pressure control system starts the vacuum pressure control, the valve body of the vacuum valve is lifted by a small amount from the fully closed position, the gas in the vacuum container is thrown out slowly, the vacuum valve is fully opened, and the gas flows at a high flow rate. This is particularly effective for improving the control response when exhausting and then the vacuum pressure control is terminated by setting the vacuum valve from the fully open state to the fully closed state.

(5) In the configuration according to any one of (1) to (4), the controller is configured to fill the operation chamber with the operation fluid to be filled, or to discharge the operation chamber from the operation chamber. It is preferable to have a diameter determining means for determining the diameter of the vacuum valve based on the amount of fluid discharged. Here, the aperture means the average inner diameter of the operation chamber.

  According to the above configuration, the diameter of the vacuum valve can be automatically determined even after the vacuum valve is installed.

(6) In the configuration described in (5), the controller performs a ramp-up control and a ramp-down control of the operation pressure when the diameter determined by the diameter determination means is equal to or less than a predetermined value, and the operation A ramp control change rate of the operation pressure is obtained based on the operation pressure measurement signal output from the pressure sensor, the lamp control change rate is compared with a predetermined threshold range, and the valve opening degree is controlled by the operation pressure. It is preferable to have controllable determination means for determining whether or not it is possible. Here, the predetermined value refers to a value serving as a reference for determining a diameter at which the piston may not move in proportion to the operating pressure. Further, the predetermined threshold range refers to an allowable range in which the valve opening is controlled by the operating pressure.

  In the vacuum valve, the piston sticks and slips when the valve is opened and closed. For example, in a vacuum valve having a diameter of 16 mm or less, the valve opening degree may not be linearly controlled by the operating pressure due to the effect of stick-slip. According to the above configuration, the vacuum pressure control system automatically recognizes whether or not the vacuum valve can control the valve opening degree with the operation pressure when the diameter of the vacuum valve is a predetermined value (for example, 16 mm) or less. And since it becomes possible to perform vacuum pressure control using a controllable vacuum valve, the reliability of vacuum pressure control can be improved.

(7) A vacuum that outputs a valve opening degree control signal for controlling the opening degree of a vacuum valve disposed between the vacuum vessel and the vacuum pump based on a deviation between the internal pressure of the vacuum vessel and a vacuum pressure target value. In the pressure control controller, the operation pressure in the operation chamber defined by the piston of the vacuum valve is measured and connected to an operation pressure sensor that outputs an operation pressure measurement signal, and based on the operation pressure measurement signal, When detecting an inflection point at which the rate of change of the operating pressure changes, and having an operation characteristic data collection means for collecting operation characteristic data of the vacuum valve, and when controlling the internal pressure of the vacuum vessel to the vacuum pressure target value On the basis of the operation characteristic data, an operation pressure control mechanism that controls the operation pressure by supplying and exhausting operation fluid to and from the operation chamber based on the operation pressure measurement signal and the valve opening control signal. Outputting the valve opening control signal generated have, and said.

  According to the above configuration, the vacuum pressure control controller, like the above-described vacuum pressure control system, detects the inflection point at which the change rate of the operating pressure changes, collects the operating characteristic data of the vacuum valve, and collects it. The valve opening degree of the vacuum valve is controlled using the operation characteristic data, and the internal pressure of the vacuum vessel is controlled. Such a vacuum pressure control controller can improve control responsiveness even with a vacuum valve not provided with a position sensor.

  Therefore, according to the present invention, it is possible to provide a vacuum pressure control system and a vacuum pressure control controller that are small, inexpensive, and have good control response.

1 is a schematic configuration diagram of a vacuum pressure control system according to an embodiment of the present invention. It is sectional drawing of the vacuum valve shown in FIG. It is a circuit diagram of the electropneumatic regulator shown in FIG. It is a block diagram which shows the structure of the controller shown in FIG. It is a figure which shows an example of the hysteresis characteristic of a vacuum valve, Comprising: A vertical axis | shaft shows a stroke (mm) and a horizontal axis | shaft shows operating pressure (MPa). It is a figure which shows the result of the experiment which investigates the relationship between operation | movement of a vacuum valve, and operation pressure, Comprising: Command (V) and stroke (mm) are shown on the left vertical axis | shaft, Operation pressure (MPa) is shown on the right vertical axis | shaft, Time (sec) is shown on the horizontal axis. It is a block diagram which shows a controllable determination function. An example of ramp-up / ramp-down control is shown. It is a block diagram which shows an operation characteristic data collection function. It is a figure explaining the detection method of an inflection point, Comprising: Command (V) is shown on the left vertical axis | shaft, Operation pressure measurement voltage (V) is shown on the right vertical axis | shaft, and time (sec) is shown on a horizontal axis. It is a figure which shows an example of operation | movement at the time of a vacuum pressure control start, Comprising: Vacuum pressure (133Pa) is shown on the left vertical axis | shaft, a command and operation pressure measurement voltage (V) are shown on the right vertical axis | shaft, and time (sec) is shown on a horizontal axis. ).

  Hereinafter, embodiments of a vacuum pressure control system and a vacuum pressure control controller according to the present invention will be described with reference to the drawings.

<Schematic configuration of vacuum pressure control system>
FIG. 1 is a schematic configuration diagram of a vacuum pressure control system 1 according to an embodiment of the present invention. The vacuum pressure control system 1 is used, for example, to control the internal pressure of the vacuum vessel 8 used for semiconductor manufacturing to a vacuum pressure target value. The vacuum pressure control system 1 includes a vacuum valve 2, an electropneumatic regulator 3 (an example of an operation pressure control mechanism), and a controller 4 (an example of a vacuum pressure control controller).

  The vacuum valve 2 is disposed on the flow path L that connects the vacuum vessel 8 and the vacuum pump 9. The controller 4 is driven by the electric power supplied from the power source 5, and the vacuum pressure sensor 8 a detects and outputs the internal pressure of the vacuum vessel 8, and the vacuum pressure target set in the host device 6 or the personal computer 7. Enter a value. The controller 4 sends a command (an example of a valve opening control signal) for controlling the valve opening (operating pressure) of the vacuum valve 2 to the electropneumatic regulator 3 based on the deviation between the vacuum pressure measurement signal and the vacuum pressure target value. Output. The electropneumatic regulator 3 supplies and exhausts the operating fluid to the vacuum valve 2 according to the valve opening control signal, and controls the operating pressure of the vacuum valve 2. The vacuum valve 2 changes the valve opening according to the operating pressure. In the vacuum vessel 8, the exhaust flow rate of the gas exhausted to the vacuum pump 9 is controlled by the vacuum valve 2, and the internal pressure is controlled to the vacuum pressure target value.

<Schematic configuration of vacuum valve 2>
FIG. 2 is a cross-sectional view of the vacuum valve 2 shown in FIG. Since the configuration of the vacuum valve 2 is the same as the conventional one, it will be briefly described here.

  The vacuum valve 2 is an air operated type single-acting valve. In the vacuum valve 2, a piston 22 is slidably loaded in a cylinder 21. In the piston 22, the operation chamber 24 is formed in an airtight manner on the valve seat side of the piston 22 by causing the packing 23 mounted on the outer peripheral surface to slide in contact with the inner wall of the cylinder 21. The operation chamber 24 communicates with an operation port 25 established in the cylinder 21 via a communication channel 26, and the operation fluid is supplied and exhausted. The piston 22 is connected to the valve body 36 via a piston rod 27 slidably held by the rod holding portion 28 of the cylinder 21, and is linearly reciprocated in the axial direction (vertical direction in the figure) integrally with the valve body 36. Exercise.

  The valve body 36 is disposed in the valve chamber 33 of the body 30. The valve chamber 33 communicates with the first port 31 and the second port 32, and a valve seat 35 is formed with a flat surface along the outer periphery of the opening 34 communicating with the first port 31. In the valve body 36, a dovetail groove 37 is formed at a position facing the valve seat 35, and an elastic seal member 38 is attached to the dovetail groove 37 so as to be elastically deformable. The valve body 36 is constantly urged in the valve seat direction by a compression spring 39 (an example of a seal load applying means), and is given a seal load that seals the elastic seal member 38 to the valve seat 35. The bellows 40 is disposed in the valve chamber 33 so as to be extendable and contractible.

<Configuration of electropneumatic regulator 3>
FIG. 3 is a circuit diagram of the electropneumatic regulator 3. The electropneumatic regulator 3 includes a first port 3a, a second port 3b, and a third port 3c. The first port 3a is connected to an operating fluid supply source that supplies the operating fluid. The second port 3b is opened to the atmosphere. The third port 3c is connected to the operation port 25 (see FIG. 2) of the vacuum valve 2.

  A supply solenoid valve 3d and an exhaust solenoid valve 3e are arranged in series between the first port 3a and the second port 3b, and a third port is provided between the supply solenoid valve 3d and the exhaust solenoid valve 3e. 3c communicates. As a result, the electropneumatic regulator 3 opens the supply solenoid valve 3d and closes the exhaust solenoid valve 3e, so that the first port 3a and the third port 3c communicate with each other and enter the operation chamber 24 via the operation port 25. Supply operating fluid. Further, the electropneumatic regulator 3 opens the exhaust solenoid valve 3e and closes the supply solenoid valve 3d so that the third port 3c and the second port 3b communicate with each other, and the operation chamber 24 is operated via the operation port 25. Drain the fluid to the atmosphere. The emergency exhaust valve 3f is provided in parallel with the exhaust electromagnetic valve 3e in order to increase the exhaust flow rate and to instantaneously close the vacuum valve 2 in an emergency. The operation pressure sensor 3k is connected to the third port 3c, measures the operation pressure of the vacuum valve 2, and outputs an operation pressure measurement voltage (an example of an operation pressure measurement signal).

  The operation command unit 3j includes a subtractor 3g, a deviation amplifier circuit 3h, and a PWM circuit 3i. The subtractor 3g obtains a deviation between the command of the controller 4 (see FIG. 1) and the operation pressure measurement voltage of the operation pressure sensor 3k. The deviation amplifying circuit 3h inputs and amplifies the deviation from the subtractor 3g. The PWM circuit 3i inputs the deviation amplified by the deviation amplification circuit 3h, generates a pulse signal for controlling the valve opening time of the supply electromagnetic valve 3d and the exhaust electromagnetic valve 3e so as to reduce the deviation, Output to the supply solenoid valve 3d and the exhaust solenoid valve 3e.

  The electropneumatic regulator 3 supplies the operating fluid to the operation chamber 24 (see FIG. 1) of the vacuum valve 2 by a pulse signal that lengthens the opening time of the supply solenoid valve 3d and shortens the opening time of the exhaust solenoid valve 3e. The operating pressure can be increased by supplying it, and the valve opening degree of the vacuum valve 2 can be increased. Further, the electropneumatic regulator 3 operates the operation fluid from the operation chamber 24 (see FIG. 1) of the vacuum valve 2 by a pulse signal that shortens the opening time of the supply solenoid valve 3d and lengthens the opening time of the exhaust solenoid valve 3e. Can be exhausted to reduce the operating pressure, and the valve opening of the vacuum valve 2 can be reduced.

<Configuration of controller 4>
FIG. 4 is a block diagram showing a hardware configuration of the controller 4. The controller 4 is a known microcomputer. In the controller 4, a central processing unit (CPU) 41, an input / output interface 42, a storage unit 43, and a voltage control unit 44 are connected via a bus 45.

  The voltage control unit 44 is connected to the power source 5 and controls the supplied power. The input / output interface 42 is connected to the electropneumatic regulator 3, the vacuum pressure sensor 8a, the host device 6, the personal computer 7, and the like, and controls input / output of electric signals.

  The storage unit 43 stores programs, data, and the like. The storage unit 43 includes, for example, an operation pressure parameter storage unit 43 a that stores an operation pressure parameter in association with the operation of the vacuum valve 2. For example, the storage unit 43 includes a bias value storage unit 43b that stores a bias value that is output when the vacuum valve 2 is opened from the fully closed state or when the vacuum valve 2 is closed from the fully opened state. Further, for example, the storage unit 43 includes a threshold range storage unit 43c that stores a predetermined threshold range. Here, the predetermined threshold range refers to an allowable range in which the valve opening is controlled by operating pressure.

<Relationship between operation of vacuum valve and inflection point of operating pressure>
First, the operation of the vacuum valve 2 will be described. FIG. 5 shows an example of hysteresis characteristics of the vacuum valve 2 having a diameter of 50 mm. The vertical axis in FIG. 5 indicates the valve opening (mm), and the horizontal axis indicates the operating pressure (MPa). Here, the aperture means the average inner diameter of the operation chamber 24 (the same applies hereinafter). As shown in A1 and A2 in the drawing, the valve opening degree of the vacuum valve 2 increases in proportion to the increase in the operating pressure. A1 in the drawing is a valve start movement point at which the valve body 36 starts to move in the counter valve seat direction from the fully closed position. The operating pressure at the valve start movement point is 0.16 MPa. A2 in the figure is a fully open point at which the valve element 36 is disposed at the fully open position and the valve opening is maximized. The operating pressure at the fully open point is 0.21 MPa. Further, as shown in A3 and A4 in the figure, the valve opening degree of the vacuum valve 2 decreases in proportion to the decrease in the operating pressure. A3 in the figure is a valve closing start point at which the valve body 36 starts to move in the valve seat direction from the fully open position. The operating pressure at the valve closing start point is 0.18 MPa. A4 in the figure is a fully closed point at which the valve body 36 seals to the valve seat 35. The operating pressure at the fully closed point is 0.13 MPa. The operating pressure has a hysteresis (0.03 MPa) between increasing and decreasing.

  Next, the inflection point of the operating pressure will be described. The inventors conducted an experiment to examine the relationship between the operation of the vacuum valve 2 and the operating pressure. In the experiment, the vacuum valve 2 having a hysteresis characteristic shown in FIG. 5 and having a diameter of 50 mm was used. Then, a command was output from the controller 4 to the electropneumatic regulator 3 at the maximum voltage (5 V) for 5 seconds, and the valve body 36 was reciprocated once between the fully closed position and the fully open position. The operating pressure at this time was measured by the operating pressure sensor 3k. Further, the position of the valve body 36 was measured by a position sensor. Here, when the command is 0 V, the operation pressure is controlled to 0 MPa. The valve opening was set to 0 mm at the position of the valve body 36 when the operating pressure was 0 MPa. The result of this experiment is shown in FIG. FIG. 6 shows the command (V) and valve opening (mm) on the left vertical axis, the operating pressure (MPa) on the right vertical axis, and the time (sec) on the horizontal axis.

  As a result of the experiment, first to fourth inflection points B1 to B4 were confirmed as shown in FIG. 6 for the operation pressure measured by the operation pressure sensor 3k. The first to fourth inflection points B1 to B4 are equal to the valve start movement detection position C1, the full open detection position C2, the valve close start detection position C3, and the full close detection position C4 detected by the position sensor. I was doing it. This principle will be described.

  When the command is 0 V, the vacuum valve 2 applies a seal load to the valve body 36 so that the compression spring 39 crushes the elastic seal member 38 between the valve body 36 and the valve seat 35 and seals it to the valve seat 35. doing. When the command is output to the vacuum valve 2, the operation chamber 24 is supplied with the operation fluid and pressurized. However, while the operating pressure is equal to or less than the spring force of the compression spring 39, the piston 22 stops at the valve seat side limit position (hereinafter also referred to as “lower limit position”), and the elastic seal member 38 of the valve body 36 is moved to the valve seat. 35 is sealed. During this time, the operation chamber 24 does not change its volume even when the operation fluid is supplied, so that the operation pressure increases rapidly (see D1 in the figure).

  When the operating pressure becomes larger than the spring force of the compression spring 39, the piston 22 starts to move in the counter valve seat direction from the lower limit position. The piston 22 moves in the counter valve seat direction in proportion to the operating pressure until the counter valve seat direction limit position (hereinafter also referred to as “upper limit position”) where movement in the counter valve seat direction is limited. At this time, the piston 22 moves integrally with the valve body 36 via the piston rod 27, and increases the separation distance (valve opening degree) between the valve body 36 and the valve seat 35 according to the operating pressure. During this time, the volume of the operation chamber 24 increases according to the supply of the operation fluid, so that the operation pressure increases slowly (see D2 in the figure).

  Therefore, when the piston 22 starts to move, that is, at the valve start movement detection position C1 where the valve body 36 starts to move in the counter valve seat direction from the fully closed position, the increase rate of the operating pressure changes from a large state to a small state. One inflection point B1 (an example of a large-small increase inflection point) appears.

  The piston 22 stops when it moves to the upper limit position and arranges the valve body 36 at the fully open position (maximizing the valve opening). However, the operation fluid is supplied to the operation chamber 24 until the pressure becomes the same as the original pressure of the operation fluid. In this case, since the volume of the operation chamber 24 does not increase even when the operation fluid is supplied, the operation pressure rapidly increases (see D3 in the figure).

  Therefore, when the piston 22 reaches the upper limit position, that is, at the fully open detection position C2 where the valve element 36 is disposed at the fully open position, the second inflection point where the increase rate of the operating pressure changes from a small state to a large state. B2 (an example of a small-large increase inflection point) appears.

  When the operating pressure reaches the same pressure as the original pressure of the operating fluid, it becomes stable (see D4 in the figure). When the command is set to 0 V, the operation fluid is exhausted from the operation chamber 24 and the operation pressure starts to decrease. However, since the operation chamber 24 is pressurized even after the piston 22 moves to the upper limit position, the vacuum valve 2 does not immediately move in the valve seat direction even if the operation fluid is exhausted from the operation chamber 24. . The piston 22 does not move in the valve seat direction until the operating pressure becomes smaller than the resultant force of the spring force of the compression spring 39 and the vacuum pressure of the valve chamber 33. During this time, the volume of the operation chamber 24 does not change even when the operation fluid is exhausted, so that the operation pressure rapidly decreases (see D5 in the figure).

  Thereafter, when the operation fluid is further exhausted from the operation chamber 24 and the operation pressure decreases, the piston 22 starts to move in the valve seat direction. The piston 22 moves in the valve seat direction in proportion to the decrease in the operating pressure until the valve element 36 contacts the valve seat 35 and is restricted from moving. During this time, the volume of the operation chamber 24 decreases according to the exhaust of the operation fluid, so that the operation pressure decreases slowly (see D6 in the figure).

  Therefore, when the piston 22 starts to move in the valve seat direction from the upper limit position, that is, in the valve closing start detection position C3 where the valve body 36 starts to move in the valve seat direction, the operating pressure reduction rate is changed from a large state to a small state. A changing third inflection point B3 (an example of a large-small decrease inflection point) appears.

  Since the command of the vacuum valve 2 is 0 V, the operation fluid is exhausted from the operation chamber 24 until the operation pressure becomes 0 MPa even after the valve body 36 is sealed to the valve seat 35. During this time, the volume of the operation chamber 24 does not change even when the operation fluid is exhausted, so that the operation pressure rapidly decreases (see D7 in the figure).

  Therefore, when the piston 22 reaches the lower limit position, that is, at the fully closed detection position C4 where the valve element 36 is disposed at the fully closed position, the fourth change in which the decreasing rate of the operating pressure changes from a small state to a large state. Inflection point B4 (an example of a small-large decrease inflection point) appears.

  The operation pressures at the first to fourth inflection points B1 to B4 shown in FIG. 6 coincide with the operation pressures at the operation points A1 to A4 shown in FIG. Therefore, the operation characteristic data of the vacuum valve 2 can be collected by detecting the inflection point of the operating pressure.

  That is, the operating pressure (0.16 MPa) at the first inflection point B1 shown in FIG. 6 matches the operating pressure at the valve start movement point A1 shown in FIG. Therefore, the operation pressure at the first inflection point B1 can be detected as the valve start start operation pressure parameter at the valve start movement point A1.

  Further, the operation pressure (0.21 MPa) at the second inflection point B2 shown in FIG. 6 matches the operation pressure at the fully open point A2 shown in FIG. Therefore, the operating pressure at the second inflection point B2 can be detected as the operating pressure parameter at the fully opened point A2.

  Further, the operating pressure (0.18 MPa) at the third inflection point B3 shown in FIG. 6 matches the operating pressure at the valve closing start point A3 shown in FIG. Therefore, the operation pressure at the third inflection point B3 can be detected as the operation pressure parameter at the valve closing start point A3.

  Further, the operating pressure (0.13 MPa) at the fourth inflection point B4 shown in FIG. 6 matches the operating pressure at the fully closed point A4 shown in FIG. Therefore, the operation pressure at the fourth inflection point B4 can be detected as the operation pressure parameter for the fully closed point A4.

  Further, the differential pressure (0.03 MPa) between the operating pressure (0.13 MPa) at the fourth inflection point B4 and the operating pressure (0.16 MPa) at the first inflection point B1, and the operating pressure at the second inflection point B2. The differential pressure (0.03 MPa) between the operating pressure (0.18 MPa) at (0.21 MPa) and the third inflection point B3 matches the hysteresis of the vacuum valve 2. Accordingly, the differential pressure between the operating pressure at the fourth inflection point B4 (operating pressure parameter when fully closed) and the operating pressure at the first inflection point B1 (operating pressure parameter during valve start operation), and the second inflection point A bias value for eliminating hysteresis can be set based on the differential pressure between the operating pressure of B2 (operating pressure parameter when fully opened) and the operating pressure of the third inflection point B3 (operating pressure parameter when fully closed).

<Operation characteristic data collection method>
Next, the operation characteristic data collection method will be described. The operating characteristic data collection method is executed, for example, when a semiconductor manufacturing apparatus is started. If the vacuum valve 2 continues the fully closed state, the packing 23 is fixed to the inner wall of the cylinder 21 or it is difficult to get used to it. Therefore, the controller 4 performs a habituation operation, and then detects the inflection point and collects operation characteristic data. The controller 4 automatically determines the caliber of the vacuum valve 2 using the acclimation operation, and if the determined caliber is a predetermined value or less, whether or not the valve opening degree of the vacuum valve 2 can be controlled by the operation pressure. It is automatically determined.

<About the controllable determination function executed during the habituation operation>
FIG. 7 is a block diagram illustrating the controllable determination function. The controller 4 outputs a command to the electropneumatic regulator 3 so that the valve body 36 is reciprocated once at a high speed between the fully closed position and the fully open position by the habituation operation command means 51. Thereby, the sticking of the packing 23 is eliminated, or the sliding resistance generated between the packing 23 and the cylinder 21 is stabilized.

  As for the vacuum valve 2, the filling amount of the operation fluid differs depending on the diameter. Therefore, the aperture determining means 52 inputs the operating pressure measurement voltage of the operating pressure sensor 3k when the acclimatization operation command means 51 opens and closes the vacuum valve 2, and calculates the amount of operation fluid charged. Then, the diameter determining means 52 automatically recognizes the diameter based on the calculated filling amount.

  As the aperture of the vacuum valve 2 is smaller, the valve opening / closing operation is affected by the sliding resistance of the packing 23. For example, the diameter of the vacuum valve 2 has a diameter of 16 mm, a diameter of 25 mm, a diameter of 40 mm and a diameter of 50 mm. In some cases, the valve opening cannot be controlled. Therefore, when the aperture automatically recognized by the aperture determining means 52 is equal to or less than a predetermined value (for example, a diameter of 16 mm or less) serving as a reference for the aperture whose valve opening cannot be controlled by the operating pressure, the control possible determining means. 53 is executed. When the aperture is larger than the predetermined value, the operation characteristic collection command control means 61 (see FIG. 9) described later is executed.

  In the controllable determination means 53, the controller 4 outputs a command to the electropneumatic regulator 3 so as to perform ramp-up control and ramp-down control of the operating pressure, as indicated by E1 and E2 in FIG. The controllability determining means 53 calculates a lamp control change rate at which the operating pressure changes within a predetermined time during the ramp-up control, and the calculated lamp control change rate is a threshold range stored in the threshold range storage unit 43c. Compare with The controllable determination means 53 determines that control is possible if the ramp control change rate is within the threshold range (below the upper threshold value, and higher than the lower threshold value). In this case, an operation characteristic collection command control means 61 (see FIG. 9) described later is executed. On the other hand, the controllability determining means 53 determines that control is impossible when the ramp control change rate is outside the threshold range (larger than the upper threshold or smaller than the lower threshold). In this case, the controller 4 does not execute an operation characteristic collection command control means 61 (see FIG. 9) described later, and notifies the host device 6 or the personal computer 7 that control is impossible.

  The controller 4 compares the upper limit value with the original pressure of the operating fluid when the operating pressure is stabilized at the upper limit value, as indicated by E3 in FIG. If the upper limit value is the same as the original pressure, it is determined that the vacuum valve 2 is normal. On the other hand, if the upper limit value is smaller than the original pressure, there is a high possibility that a malfunction such as leakage of the operating fluid from the packing 23 has occurred, so the host device 6 or the personal computer 7 is warned of an abnormality.

  Further, the controller 4 may measure a response delay from when the command is set to 0 V to when the operation pressure starts to decrease from the upper limit value, and may additionally recognize the aperture by the response delay. If the aperture is double-recognized in this way, the aperture determination accuracy is improved.

<Operation characteristic data collection function>
FIG. 9 is a block diagram illustrating the operation characteristic data collection function. FIG. 10 is a diagram for explaining an inflection point detection method, in which the left vertical axis indicates command (V), the right vertical axis indicates operation pressure measurement voltage (V), and the horizontal axis indicates time (sec). Indicates. The controller 4 outputs a command at a maximum value (for example, 5 V) for a predetermined time (for example, 2 seconds) by the command control means 61 for collecting operating characteristics shown in FIG. During this time, the operation pressure measurement signal input means 62 inputs the operation pressure measurement voltage of the operation pressure sensor 3k, and acquires operation pressure data as shown in FIG.

  The change rate calculation means 63 shown in FIG. 9 calculates the change rate of the operating pressure based on the operating pressure data. And the inflection point detection means 64 detects the 1st-4th inflection points B1-B4 from which the change rate of operation pressure changes based on the operation pressure data of FIG. The operation pressure parameter storage unit 65 shown in FIG. 9 stores the operation pressure at the first inflection point B1 in the operation pressure parameter storage unit 43a as the operation pressure parameter at the time of starting the valve. Further, the operating pressure parameter storage means 65 stores the operating pressure at the second inflection point B2 in the operating pressure parameter storage unit 43a as the fully open operating pressure parameter. The operation pressure parameter storage means 65 stores the operation pressure at the third inflection point B3 in the operation pressure parameter storage unit 43a as the operation pressure parameter at the time of valve closing start. In addition, the operating pressure parameter storage means 65 stores the operating pressure at the fourth inflection point B4 in the operating pressure parameter storage unit 43a as the fully closed operating pressure parameter. In this embodiment, the operation characteristic data collection means includes the operation characteristic collection command control means 61, the operation pressure measurement signal input means 62, the change rate calculation means 63, the inflection point detection means 64, and the operation pressure parameter storage means 65. 60 is configured.

  Then, the bias value automatic setting means 66 shown in FIG. 9 includes the differential pressure between the operation pressure at the first inflection point B1 and the operation pressure at the fourth inflection point B4, and the operation pressure at the second inflection point B2. A bias value is automatically set based on the differential pressure with respect to the operating pressure at the third inflection point B3 and stored in the bias value storage unit 43b.

<Vacuum pressure control function>
When the operation characteristic data is detected as described above, the controller 4 uses the data stored in the operation pressure parameter storage unit 43a and the bias value storage unit 43b to instruct the valve opening (operation pressure) of the vacuum valve 2. An opening control signal is output to the electropneumatic regulator 3, and the internal pressure of the vacuum vessel 8 is controlled to a vacuum pressure target value.

  For example, when the internal pressure of the vacuum vessel 8 is reduced from the atmospheric pressure to the vacuum pressure target value, the fully closed vacuum valve 2 has a large differential pressure between the primary side and the secondary side. Therefore, the controller 4 outputs a valve opening control signal for finely controlling the valve opening of the vacuum valve 2 to the electropneumatic regulator 3. Thereby, the vacuum vessel 8 is slowly exhausted so as not to wind up the particles in the vacuum vessel 8, and the internal pressure slowly decreases.

  The slow exhaust operation will be specifically described with reference to FIG. FIG. 11 is a diagram showing an example of the operation at the start of vacuum pressure control, in which the left vertical axis indicates the vacuum pressure (133 Pa), the right vertical axis indicates the command and the operating pressure measurement voltage (V), and the horizontal axis Shows time (sec).

  The controller 4 outputs the bias value stored in the bias value storage unit 43b to the electropneumatic regulator 3, as indicated by G1 in FIG. Then increase the command gradually.

  When the electropneumatic regulator 3 receives the bias value, the electro-pneumatic regulator 3 uses the deviation between the bias value input from the controller 4 and the operation pressure measurement voltage input from the operation pressure sensor 3k to set the valve open time of the supply solenoid valve 3d for exhaust. A pulse signal that is longer than the valve opening time of the electromagnetic valve 3e is output. When the vacuum valve 2 is fully closed, the electropneumatic regulator 3 simultaneously opens and closes the supply solenoid valve 3d and the exhaust solenoid valve 3e, and stores them in the operation pressure parameter storage unit 43a as indicated by H in the figure. The operation pressure in the operation chamber 24 is controlled so as to coincide with the fully closed operation pressure parameter. Therefore, in the electropneumatic regulator 3, the supply solenoid valve 3 d and the exhaust solenoid valve 3 e follow the change of the pulse signal with good responsiveness and supply the operation fluid to the operation chamber 24. In addition, the vacuum valve 2 has no dead zone because the operation chamber 24 is preloaded to the fully closed operation pressure parameter when the vacuum valve 2 is in the fully closed state. Therefore, as soon as the command is output, the valve body 36 moves from the fully closed position to the counter valve seat direction and reaches the valve start moving position.

  Thereafter, the electropneumatic regulator 3 gradually increases the valve opening time of the supply solenoid valve 3d to be longer than the valve opening time of the exhaust solenoid valve 3e, and gradually increases the operating pressure. Thereby, the vacuum valve 2 moves the valve body 36 from the valve starting movement point in the counter valve seat direction in accordance with the increase of the operation pressure, and relaxes the elastic deformation amount of the elastic seal member 38. Since the operation chamber 24 is not unnecessarily decompressed when the vacuum valve 2 is in the fully closed state, when the controller 4 outputs a command for finely controlling the valve opening, the valve body 36 is counteracted from the fully closed position. The time to start moving immediately in the seating direction and from the fully closed state to the valve open state is shortened. As described above, when the vacuum valve 2 opens the valve while reducing the elastic deformation amount of the elastic seal member 38, the gas leaks from the space between the elastic seal member 38 and the valve seat 35 to the vacuum pump 9 side. At first, the internal pressure begins to drop.

  The controller 4 minutely controls the valve opening degree of the vacuum valve 2 until the vacuum vessel 8 is depressurized to such an extent that particles are not rolled up. When the pressure is reduced to such an extent that the vacuum vessel 8 does not roll up the particles, the controller 4 matches the operating pressure with the fully-open operating pressure parameter stored in the operating pressure parameter storage unit 43a as indicated by G2 in the figure. Command is output to the electropneumatic regulator 3.

  The electropneumatic regulator 3 opens the supply solenoid valve 3d and closes the exhaust solenoid valve 3e to increase the supply amount of the operating fluid. When the operating pressure reaches the fully open operating pressure parameter, the electropneumatic regulator 3 simultaneously opens and closes the supply solenoid valve 3d and the exhaust solenoid valve 3e to stop supplying the operating fluid. Therefore, after the valve body 36 reaches the fully open position, the operation fluid is not supplied to the operation chamber 24 and the operation pressure is maintained at the fully open operation pressure parameter. Since the vacuum valve 2 is fully opened without wastefully supplying the operation fluid to the operation chamber 24, the time for making the fully open state is shortened. When the vacuum valve 2 is fully opened in this way, the vacuum container 8 is evacuated with a large flow rate, and the internal pressure reaches the vacuum pressure target value in a short time.

  When the controller 4 inputs a vacuum pressure control end instruction from the host device 6, the controller 4 outputs a command so that the operation pressure matches the fully closed operation pressure parameter. Then, the electropneumatic regulator 3 exhausts the operating fluid from the operation chamber 24 by closing the supply electromagnetic valve 3d and opening the exhaust electromagnetic valve 3e, thereby reducing the operation pressure. The vacuum valve 2 moves the valve element 36 in the valve seat direction from the fully open position in accordance with a decrease in the operating pressure. At this time, when the vacuum valve 2 is in the fully open state, the operating pressure is controlled to the fully open operating pressure parameter, so there is no dead zone. Therefore, as soon as the operation fluid is exhausted from the operation chamber 24, the valve body 36 starts to move in the valve seat direction. Since the operation chamber 24 is not unnecessarily pressurized when the vacuum valve 2 is in the fully opened state, when a command for closing the valve is output, the valve body 36 starts to move immediately in the valve seat direction, and the fully open state. From time to time to close the valve. When the operating pressure is reduced to the fully closed operating pressure parameter, the electropneumatic regulator 3 opens and closes the supply solenoid valve 3d and the exhaust solenoid valve 3e simultaneously. Therefore, in the vacuum valve 2, the operation fluid is not exhausted from the operation chamber 24 after the valve body 36 is sealed to the valve seat 35. Therefore, the time until the vacuum valve 2 is fully closed is shortened. As the vacuum valve 2 is fully closed in this manner, the vacuum vessel 8 is blocked by the vacuum valve 2 through the flow path L, and gas is not exhausted.

  The controller 4 controls the operating pressure of the vacuum valve 2 to the fully-closed operating pressure parameter until the next vacuum pressure control start instruction is input. As a result, the vacuum valve 2 is fully closed while the operation chamber 24 is preloaded.

<About control response confirmation test>
The inventors performed slow exhaust operation in the example and the comparative example, and performed a control response confirmation test. In the example, as in the above-described embodiment, the vacuum valve 2 is operated to open and close, the first to fourth inflection points B1 to B4 are detected based on the operation pressure data, and the operation characteristic data of the vacuum valve 2 is obtained. (Fully closed operation pressure parameter, fully open operation pressure parameter, valve start movement operation pressure parameter, valve close start operation pressure parameter, bias value) were automatically collected and used to perform slow exhaust. In the comparative example, the slow exhaust was performed without preloading the vacuum valve 2. In the comparative example, the bias value was set manually. Other device conditions and control conditions are the same in the example and the comparative example.

  As a result, as shown by t2 in FIG. 11, in the comparative example, the response time from the output of the command until the internal pressure of the vacuum vessel 8 began to decrease took 30 to 40 seconds. On the other hand, in the example, as indicated by t1 in FIG. 11, the response time from the output of the command until the internal pressure of the vacuum vessel 8 starts to decrease was 7 seconds. This is presumably because the working chamber 24 was preloaded as shown in FIG. 11H to eliminate the dead zone. In addition, it is considered that the example was able to set a bias value that matched the hysteresis of the vacuum valve 2 based on the first to fourth inflection points B1 to B4.

<Summary>
The vacuum pressure control system 1 of the present embodiment includes an operation chamber 24 defined by a piston 22, a valve body 36 that moves integrally with the piston 22, a valve seat 35 that contacts or separates from the valve body 36, and a valve A compression spring 39 for applying a sealing load for sealing the body 36 to the valve seat 35, the vacuum valve 2 disposed between the vacuum vessel 8 and the vacuum pump 9, and the internal pressure and vacuum pressure target of the vacuum vessel 8. In a vacuum pressure control system 1 having a controller 4 that outputs a command for controlling the valve opening degree of the vacuum valve 2 based on a deviation from the value, an operation pressure sensor 3k that measures an operation pressure and outputs an operation pressure measurement voltage The controller 4 includes an electropneumatic regulator 3 (an example of an operation pressure control mechanism) that supplies and exhausts the operation fluid to the operation chamber 24 based on the command and the operation pressure measurement voltage and controls the operation pressure. It has an operation characteristic data sampling means 60 for detecting an inflection point where the change rate of the operation pressure changes based on the operation pressure measurement voltage, and acquires the operation characteristic data of the vacuum valve 2, and controls the internal pressure to the vacuum pressure target value. In this case, the operation characteristic data is used to generate a command and output it to the electropneumatic regulator 3.

  According to this configuration, the vacuum pressure control system 1 uses the first to fourth inflection points B1 to B4 at which the operating pressure of the vacuum valve 2 measured by the operating pressure sensor 3k changes the rate of change. The operation characteristic data is collected, and the controller 4 generates a command using the data and outputs the command to the electropneumatic regulator 3. The electropneumatic regulator 3 controls the operation pressure of the vacuum valve 2 based on the operation pressure measurement voltage of the operation pressure sensor 3 k and the command of the controller 4. Thereby, the vacuum pressure control system 1 opens and closes the vacuum valve 2 according to the instruction of the controller 4, and controls the flow rate of the gas flowing from the vacuum vessel 8 to the vacuum pump 9, whereby the internal pressure of the vacuum vessel 8 becomes the vacuum pressure target value. To reach. The vacuum pressure control system 1 grasps the operation of the vacuum valve 2 from the first to fourth inflection points B1 to B4 of the operation pressure measured by the operation pressure sensor 3k without providing a position sensor in the vacuum valve 2. Since the valve opening degree of the vacuum valve 2 is controlled, the system can be made small and inexpensive. Further, since the vacuum pressure control system 1 controls the valve opening degree of the vacuum valve 2 using the operation characteristic data unique to the vacuum valve 2, the dead zone where the valve opening degree does not change even when the operating fluid is supplied and exhausted is eliminated. Thus, control responsiveness can be improved.

  In the vacuum pressure control system 1 of the present embodiment, the operation characteristic data collection means 60 is a fourth variation in which the decrease rate changes from a small state to a large state within a range in which a decrease in the operation pressure is detected based on the operation pressure measurement voltage. The operation point data is collected by detecting the bending point B4 and storing the operation pressure at the fourth inflection point B4 as the operation pressure parameter for the fully closed point A4 where the valve body 36 seals to the valve seat 35. In addition, the controller 4 is characterized in that when the vacuum valve 2 is fully closed, the controller 4 generates a command so that the operation pressure matches the operation pressure parameter when fully closed.

  According to this configuration, the vacuum pressure control system 1 stops the operation fluid from the operation chamber 24 when the operation pressure in the operation chamber 24 reaches the fully closed operation pressure parameter. After that, the operation fluid is not exhausted from the operation chamber 24 in vain. Therefore, the vacuum pressure control system 1 can shorten the time required for the vacuum valve 2 to be fully closed and the time required for the next valve open state to improve the control response.

  In the vacuum pressure control system 1 of the present embodiment, the operation characteristic data collection means 60 is a second variable that changes from a small increase state to a large state within a range in which an increase in the operation pressure is detected based on the operation pressure measurement voltage. By collecting the operation characteristic data by detecting the bending point B2 and storing the operation pressure at the second inflection point B2 as the operation pressure parameter at the fully open point A2 at which the valve opening is maximized, the controller 4 Is characterized in that when the vacuum valve is fully opened, a command is generated so that the operating pressure matches the operating pressure parameter when fully opened.

  According to this configuration, in the vacuum pressure control system 1, when the operation pressure in the operation chamber 24 reaches the operation pressure parameter when fully opened, the operation fluid is not supplied to the operation chamber 24, so that the vacuum valve 2 is fully opened. Later, the operation fluid is not wastedly supplied to the operation chamber 24. In such a vacuum pressure control system 1, the time until the vacuum valve 2 is fully opened and the time until the next valve is closed are shortened, and the control responsiveness can be improved.

  In the vacuum pressure control system 1 of the present embodiment, the operation characteristic data collection means 60 is a first change in which the increase rate changes from a large state to a small state within a range in which an increase in the operation pressure is detected based on the operation pressure measurement voltage. The inflection point B1 is detected, and the operation pressure at the first inflection point B1 is stored as the operation pressure parameter at the time of valve start movement of the valve start movement point A1 at which the valve body 36 starts to move away from the valve seat 35, and the operation pressure measurement voltage Is detected, the third inflection point B3 that changes from a large decrease rate to a small decrease state is detected, and the valve body 36 is at the fully open position with the operation pressure at the third inflection point B3. The operation characteristic data is collected by storing it as the valve closing start operation pressure parameter of the valve closing start point A3 which starts to move from the valve seat direction to the controller 4. The bias value automatic setting means 66 that automatically sets the bias value based on the differential pressure between the operating pressure parameter at the time of starting the valve and the valve, and the differential pressure between the operating pressure parameter at the time of fully opening and the operating pressure parameter at the time of closing the valve. It is preferable to output the bias value to the electropneumatic regulator 3 when the vacuum valve 2 is opened from the fully closed state and when the vacuum valve 2 is closed from the fully opened state.

  According to this configuration, the vacuum pressure control system 1 outputs a bias value when the vacuum valve 2 is in the fully closed state, whereby the valve body 36 immediately moves from the fully closed position to the valve start moving position, Response time during operation can be shortened. Further, by outputting a bias value when the vacuum valve 2 is in a fully open state, the valve element 36 moves immediately from the fully open position to the valve closing start position, and the response time at the time of starting the valve closing can be shortened. This is because when the vacuum pressure control system 1 starts the vacuum pressure control, the valve body 36 of the vacuum valve 2 is slightly increased from the fully closed position, and the gas in the vacuum vessel 8 is slowly exhausted, and then the vacuum valve 2 is fully opened. This is particularly effective in improving control response when the gas is exhausted at a large flow rate and the vacuum pressure control is terminated after the vacuum valve 2 is fully closed from the fully open state.

  In the vacuum pressure control system 1 of the present embodiment, the controller 4 has a diameter determining means 52 that determines the diameter of the vacuum valve 2 based on the amount of operation fluid charged in the operation chamber 24.

  According to this configuration, the vacuum pressure control system 1 can automatically determine the diameter of the vacuum valve 2 even after the vacuum valve 2 is installed in the flow path L between the vacuum vessel 8 and the vacuum pump 9. it can.

  In the vacuum pressure control system 1 of the present embodiment, the controller 4 performs ramp-up control and ramp-down control of the operating pressure when the aperture determined by the aperture determining means 52 is a predetermined value or less, and the operating pressure sensor 3k is Control that determines the ramp control change rate of the operating pressure based on the operating pressure measurement voltage that is output, compares the ramp control change rate with a predetermined threshold range, and determines whether the valve opening can be controlled by the operating pressure And a possibility determining means 53.

  According to this configuration, the vacuum pressure control system automatically determines whether or not the vacuum valve 2 can control the valve opening degree with the operation pressure when the aperture of the vacuum valve is a predetermined value (for example, 16 mm) or less. Recognizing and controlling the vacuum pressure using the controllable vacuum valve 2 makes it possible to improve the reliability of the vacuum pressure control.

  The controller 4 (an example of a controller for vacuum pressure control) of the present embodiment uses a command for controlling the valve opening degree of the vacuum valve 2 disposed between the vacuum vessel 8 and the vacuum pump 9 as an internal pressure of the vacuum vessel 8. In the controller 4 that outputs based on the deviation from the target vacuum pressure value, the operation pressure in the operation chamber 24 partitioned by the piston 22 of the vacuum valve 2 is measured and connected to the operation pressure sensor 3k that outputs the operation pressure measurement voltage. The operation characteristic data collecting means 60 for detecting the first to fourth inflection points B1 to B4 where the change rate of the operation pressure changes based on the operation pressure measurement voltage and collecting the operation characteristic data of the vacuum valve 2 When the internal pressure of the vacuum vessel 8 is controlled to the vacuum pressure target value, the operation pressure is controlled by supplying and exhausting the operation fluid to the operation chamber 24 based on the operation pressure measurement voltage and the command. In that electropneumatic regulator 3, it outputs a command generated based on the motion characteristic data, characterized by.

  According to the above configuration, the controller 4 detects the first to fourth inflection points B <b> 1 to B <b> 4 at which the change rate of the operating pressure changes, similarly to the above-described vacuum pressure control system 1, and the operating characteristics of the vacuum valve 2. Data is collected, the opening degree of the vacuum valve 2 is controlled using the collected operating characteristic data, and the internal pressure of the vacuum vessel 8 is controlled. Such a controller 4 can improve control responsiveness even with a vacuum valve 2 that does not include a position sensor.

  Therefore, according to the present embodiment, it is possible to provide the vacuum pressure control system 1 and the controller 4 that are small, inexpensive, and have good control response.

In addition, this invention is not limited to the said embodiment, Various application is possible.
For example, the caliber determination means 52 inputs the operation pressure measurement voltage of the operation pressure sensor 3k when the habituation operation command means 51 opens and closes the vacuum valve 2, and calculates the discharge amount of the operation fluid discharged from the operation chamber 24. The diameter of the vacuum valve 2 may be automatically recognized based on the calculated exhaust amount. According to this, the diameter of the vacuum valve 2 can be determined even after the vacuum valve 2 is installed in the flow path L between the vacuum vessel 8 and the vacuum pump 9, as in the case of determining the diameter based on the filling amount of the operating fluid. Can be automatically determined.

1 Vacuum pressure control system 2 Vacuum valve 3 Electropneumatic regulator (an example of operating pressure control mechanism)
3k Operation pressure sensor 4 Controller (Example of controller for vacuum pressure control)
22 Piston 24 Cylinder 35 Valve seat 36 Valve body 39 Compression spring (an example of sealing load applying means)
52 Diameter determining means 53 Controllable determining means 60 Operating characteristic data collecting means 66 Bias value automatic setting means A1 Valve start movement point A2 Fully open point A3 Valve close start point A4 Fully closed points B1 to B4 First to fourth inflection points ( Example of large-small increase inflection point, small-large increase inflection point, large-small decrease inflection point, small-large decrease inflection point)

Claims (7)

An operation chamber defined by a piston, a valve body that moves integrally with the piston, a valve seat that contacts or separates from the valve body, and a seal that applies a seal load that seals the valve body to the valve seat A vacuum valve disposed between the vacuum vessel and the vacuum pump, and a valve opening degree of the vacuum valve is controlled based on a deviation between an internal pressure of the vacuum vessel and a target value of the vacuum pressure. In a vacuum pressure control system having a controller that outputs a valve opening control signal,
An operation pressure sensor that measures the operation pressure and outputs an operation pressure measurement signal;
An operation pressure control mechanism for supplying and exhausting an operation fluid to and from the operation chamber based on the valve opening control signal and the operation pressure measurement signal and controlling the operation pressure;
The controller is
Detecting an inflection point at which the rate of change of the operation pressure changes based on the operation pressure measurement signal, and having operation characteristic data collection means for collecting operation characteristic data of the vacuum valve;
When controlling the internal pressure to the vacuum pressure target value, generating the valve opening control signal using the operation characteristic data, and outputting to the operating pressure control mechanism,
Features a vacuum pressure control system. The vacuum pressure control system according to claim 1,
The operation characteristic data collection means detects a small-large decrease inflection point where the decrease rate changes from a small state to a large state within a range in which a decrease in the operation pressure is detected based on the operation pressure measurement signal, Collecting the operating characteristic data by storing the operating pressure at the small-large decreasing inflection point as a fully-closed operating pressure parameter of a fully-closed point at which the valve element seals the valve seat;
The controller generates the valve opening control signal so as to match the operation pressure with the operation pressure parameter when fully closed when the vacuum valve is fully closed;
Features a vacuum pressure control system. In the vacuum pressure control system according to claim 1 or 2,
The operation characteristic data collection means detects a small-large increase inflection point where the increase rate changes from a small state to a large state in a range where the increase in the operation pressure is detected based on the operation pressure measurement signal, Collecting the operating characteristic data by storing the operating pressure at a small-large increase inflection point as a fully-opening operating pressure parameter of a fully-opening point at which the valve opening is maximized;
The controller generates the valve opening control signal so as to match the operation pressure with the operation pressure parameter when fully opened when the vacuum valve is fully opened;
Features a vacuum pressure control system. The vacuum pressure control system according to claim 3,
The operation characteristic data collection means detects a large-small increase inflection point where the increase rate changes from a large state to a small state within a range in which the increase in the operation pressure is detected based on the operation pressure measurement signal, The operation pressure at the large-to-small increase inflection point is stored as a valve start movement operation pressure parameter of the valve start movement point at which the valve body starts to move away from the valve seat, and the operation pressure is determined based on the operation pressure measurement signal. When detecting a decrease in the large-to-small decrease inflection point where the decrease rate changes from a large state to a small state, the operating pressure at the large-to-small decrease inflection point is detected from the fully open position. Collecting the operating characteristic data by storing it as a valve closing start operating pressure parameter of a valve closing start point that starts moving in the seat direction;
The controller is
Based on the differential pressure between the fully closed operating pressure parameter and the valve start operating pressure parameter, and the differential pressure between the fully opened operating pressure parameter and the valve closed starting pressure parameter, the bias value is automatically Automatic bias value setting means for automatically setting,
Outputting the bias value to the operating pressure control mechanism when opening the vacuum valve from a fully closed state and when closing the vacuum valve from a fully open state;
Features a vacuum pressure control system. In the vacuum pressure control system according to any one of claims 1 to 4,
The controller has a diameter determining means for determining a diameter of the vacuum valve based on a filling amount of the operation fluid filled in the operation chamber or a discharge amount of the operation fluid discharged from the operation chamber. ,
Features a vacuum pressure control system. The vacuum pressure control system according to claim 5,
The controller performs ramp-up control and ramp-down control of the operation pressure when the aperture determined by the aperture determination means is equal to or less than a predetermined value, and based on the operation pressure measurement signal output by the operation pressure sensor A controllability determining means for determining a lamp control change rate of the operating pressure and comparing the lamp control change rate with a predetermined threshold range to determine whether or not the valve opening can be controlled by the operating pressure. Having
Features a vacuum pressure control system. For vacuum pressure control that outputs a valve opening control signal for controlling the valve opening of a vacuum valve disposed between the vacuum vessel and the vacuum pump based on the deviation between the internal pressure of the vacuum vessel and the target value of the vacuum pressure In the controller
Measuring an operating pressure in an operating chamber defined by the piston of the vacuum valve, and being connected to an operating pressure sensor that outputs an operating pressure measurement signal;
Detecting an inflection point where the rate of change of the operating pressure changes based on the operating pressure measurement signal, and having operating characteristic data collecting means for collecting operating characteristic data of the vacuum valve;
When controlling the internal pressure of the vacuum vessel to the vacuum pressure target value, the operation pressure is controlled by supplying and exhausting operation fluid to and from the operation chamber based on the operation pressure measurement signal and the valve opening control signal. Outputting the valve opening degree control signal generated based on the operation characteristic data to the operation pressure control mechanism
A controller for vacuum pressure control.

Images